<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019e3c65-a0a9-75e6-9bc0-6dcb5292a3eb,g:d1256a4a-1746-421b-b591-8750b55b7ea7-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/ConsolidatedBalanceSheets" xlink:type="simple" xlink:href="fihl-20260630.xsd#ConsolidatedBalanceSheets"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/ConsolidatedBalanceSheets" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7cbe-896d-68a858b35753" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e3c65-a2c0-7b71-8c35-d46da3f591e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7cbe-896d-68a858b35753" xlink:to="loc_us-gaap_StatementTable_019e3c65-a2c0-7b71-8c35-d46da3f591e1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-7705-9166-b1afa48f255a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e3c65-a2c0-7b71-8c35-d46da3f591e1" xlink:to="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-7705-9166-b1afa48f255a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7705-9166-b1afa48f255a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-7705-9166-b1afa48f255a" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7705-9166-b1afa48f255a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-792b-a6e8-e4fe881a22bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-7705-9166-b1afa48f255a" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-792b-a6e8-e4fe881a22bc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FixedMaturitiesMember_019e3c65-a2c0-7c57-8657-0b114167fc83" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FixedMaturitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-792b-a6e8-e4fe881a22bc" xlink:to="loc_us-gaap_FixedMaturitiesMember_019e3c65-a2c0-7c57-8657-0b114167fc83" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestmentsMember_019e3c65-a2c0-7119-a180-443887e9c3bf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-792b-a6e8-e4fe881a22bc" xlink:to="loc_us-gaap_ShortTermInvestmentsMember_019e3c65-a2c0-7119-a180-443887e9c3bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a2c0-74db-9ac5-961638e3be15" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e3c65-a2c0-7b71-8c35-d46da3f591e1" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a2c0-74db-9ac5-961638e3be15" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e3c65-a2c0-74db-9ac5-961638e3be15_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a2c0-74db-9ac5-961638e3be15" xlink:to="loc_us-gaap_RelatedPartyDomain_019e3c65-a2c0-74db-9ac5-961638e3be15_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e3c65-a2c0-73a1-b6a6-a56f80a86167" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a2c0-74db-9ac5-961638e3be15" xlink:to="loc_us-gaap_RelatedPartyDomain_019e3c65-a2c0-73a1-b6a6-a56f80a86167" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e3c65-a2c0-7d88-8674-9a7f4bbdb573" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e3c65-a2c0-73a1-b6a6-a56f80a86167" xlink:to="loc_us-gaap_RelatedPartyMember_019e3c65-a2c0-7d88-8674-9a7f4bbdb573" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_019e3c65-a2c0-7d39-8930-a618f2df1849" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7cbe-896d-68a858b35753" xlink:to="loc_us-gaap_AssetsAbstract_019e3c65-a2c0-7d39-8930-a618f2df1849" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e3c65-a2c0-77d0-9d0f-db65fc0d76d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e3c65-a2c0-7d39-8930-a618f2df1849" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e3c65-a2c0-77d0-9d0f-db65fc0d76d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLongTermInvestments_019e3c65-a2c0-7fa8-8c4e-52890a5edd97" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLongTermInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e3c65-a2c0-7d39-8930-a618f2df1849" xlink:to="loc_us-gaap_OtherLongTermInvestments_019e3c65-a2c0-7fa8-8c4e-52890a5edd97" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Investments_019e3c65-a2c0-7905-bb41-21bed909d1e5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Investments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e3c65-a2c0-7d39-8930-a618f2df1849" xlink:to="loc_us-gaap_Investments_019e3c65-a2c0-7905-bb41-21bed909d1e5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019e3c65-a2c0-7b89-9581-9527fd585732" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e3c65-a2c0-7d39-8930-a618f2df1849" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019e3c65-a2c0-7b89-9581-9527fd585732" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalents_019e3c65-a2c0-738c-87be-f169056e2f5a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e3c65-a2c0-7d39-8930-a618f2df1849" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalents_019e3c65-a2c0-738c-87be-f169056e2f5a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedInvestmentIncomeReceivable_019e3c65-a2c0-7c91-96b3-2b88be3d071c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedInvestmentIncomeReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e3c65-a2c0-7d39-8930-a618f2df1849" xlink:to="loc_us-gaap_AccruedInvestmentIncomeReceivable_019e3c65-a2c0-7c91-96b3-2b88be3d071c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PremiumsReceivableAtCarryingValue_019e3c65-a2c0-7852-92d2-d4ace4f79202" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PremiumsReceivableAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e3c65-a2c0-7d39-8930-a618f2df1849" xlink:to="loc_us-gaap_PremiumsReceivableAtCarryingValue_019e3c65-a2c0-7852-92d2-d4ace4f79202" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherReceivables_019e3c65-a2c0-74c7-b902-ebc032f7751b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e3c65-a2c0-7d39-8930-a618f2df1849" xlink:to="loc_us-gaap_OtherReceivables_019e3c65-a2c0-74c7-b902-ebc032f7751b" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidReinsurancePremiums_019e3c65-a2c0-7c8f-8e4a-305f220f2594" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PrepaidReinsurancePremiums"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e3c65-a2c0-7d39-8930-a618f2df1849" xlink:to="loc_us-gaap_PrepaidReinsurancePremiums_019e3c65-a2c0-7c8f-8e4a-305f220f2594" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsuranceRecoverablesOnPaidLosses_019e3c65-a2c0-7bf8-9e7a-16a9bee304b1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReinsuranceRecoverablesOnPaidLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e3c65-a2c0-7d39-8930-a618f2df1849" xlink:to="loc_us-gaap_ReinsuranceRecoverablesOnPaidLosses_019e3c65-a2c0-7bf8-9e7a-16a9bee304b1" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments_019e3c65-a2c0-78bb-b7c9-121b9c67cea8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e3c65-a2c0-7d39-8930-a618f2df1849" xlink:to="loc_us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments_019e3c65-a2c0-78bb-b7c9-121b9c67cea8" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredPolicyAcquisitionCosts_019e3c65-a2c0-730f-9e60-0723d49806d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredPolicyAcquisitionCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e3c65-a2c0-7d39-8930-a618f2df1849" xlink:to="loc_us-gaap_DeferredPolicyAcquisitionCosts_019e3c65-a2c0-730f-9e60-0723d49806d8" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssets_019e3c65-a2c0-7ae5-b253-391680f7a100" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e3c65-a2c0-7d39-8930-a618f2df1849" xlink:to="loc_us-gaap_OtherAssets_019e3c65-a2c0-7ae5-b253-391680f7a100" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019e3c65-a2c0-7b76-b87f-a8d764fb17d4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e3c65-a2c0-7d39-8930-a618f2df1849" xlink:to="loc_us-gaap_Assets_019e3c65-a2c0-7b76-b87f-a8d764fb17d4" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e3c65-a2c0-7c1d-b97c-fd3810ef9837" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7cbe-896d-68a858b35753" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e3c65-a2c0-7c1d-b97c-fd3810ef9837" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract_019e3c65-a2c0-75db-a4a8-ff4ac112c91e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e3c65-a2c0-7c1d-b97c-fd3810ef9837" xlink:to="loc_us-gaap_LiabilitiesAbstract_019e3c65-a2c0-75db-a4a8-ff4ac112c91e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense_019e3c65-a2c0-7aba-be23-f997429be52b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019e3c65-a2c0-75db-a4a8-ff4ac112c91e" xlink:to="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense_019e3c65-a2c0-7aba-be23-f997429be52b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnearnedPremiums_019e3c65-a2c0-7b7f-83a8-37da181f8f1e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UnearnedPremiums"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019e3c65-a2c0-75db-a4a8-ff4ac112c91e" xlink:to="loc_us-gaap_UnearnedPremiums_019e3c65-a2c0-7b7f-83a8-37da181f8f1e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsurancePayable_019e3c65-a2c0-7e1c-99cc-aff43b5787ac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReinsurancePayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019e3c65-a2c0-75db-a4a8-ff4ac112c91e" xlink:to="loc_us-gaap_ReinsurancePayable_019e3c65-a2c0-7e1c-99cc-aff43b5787ac" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrentAndNoncurrent_019e3c65-a2c0-7898-bffc-140c408b122c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019e3c65-a2c0-75db-a4a8-ff4ac112c91e" xlink:to="loc_us-gaap_AccountsPayableCurrentAndNoncurrent_019e3c65-a2c0-7898-bffc-140c408b122c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_019e3c65-a2c0-7e30-bbed-be9e224065b5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019e3c65-a2c0-75db-a4a8-ff4ac112c91e" xlink:to="loc_us-gaap_LongTermDebt_019e3c65-a2c0-7e30-bbed-be9e224065b5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilities_019e3c65-a2c0-7737-887a-cc30357a2d96" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019e3c65-a2c0-75db-a4a8-ff4ac112c91e" xlink:to="loc_us-gaap_OtherLiabilities_019e3c65-a2c0-7737-887a-cc30357a2d96" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_019e3c65-a2c0-74ed-b9ad-796575782732" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019e3c65-a2c0-75db-a4a8-ff4ac112c91e" xlink:to="loc_us-gaap_Liabilities_019e3c65-a2c0-74ed-b9ad-796575782732" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_019e3c65-a2c0-7ef2-9fa5-bffd556f014c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e3c65-a2c0-7c1d-b97c-fd3810ef9837" xlink:to="loc_us-gaap_CommitmentsAndContingencies_019e3c65-a2c0-7ef2-9fa5-bffd556f014c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_019e3c65-a2c0-792e-97ff-c1816e3ce73f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e3c65-a2c0-7c1d-b97c-fd3810ef9837" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_019e3c65-a2c0-792e-97ff-c1816e3ce73f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_019e3c65-a2c0-7420-a92f-25111eaa51ce" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_019e3c65-a2c0-792e-97ff-c1816e3ce73f" xlink:to="loc_us-gaap_CommonStockValue_019e3c65-a2c0-7420-a92f-25111eaa51ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapital_019e3c65-a2c0-798f-8939-11628e56dca8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_019e3c65-a2c0-792e-97ff-c1816e3ce73f" xlink:to="loc_us-gaap_AdditionalPaidInCapital_019e3c65-a2c0-798f-8939-11628e56dca8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019e3c65-a2c0-7973-a610-e870d22effc6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_019e3c65-a2c0-792e-97ff-c1816e3ce73f" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019e3c65-a2c0-7973-a610-e870d22effc6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019e3c65-a2c0-7a1d-8942-85cd17eab0f7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_019e3c65-a2c0-792e-97ff-c1816e3ce73f" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019e3c65-a2c0-7a1d-8942-85cd17eab0f7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e3c65-a2c0-7681-a148-2904463d0447" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_019e3c65-a2c0-792e-97ff-c1816e3ce73f" xlink:to="loc_us-gaap_StockholdersEquity_019e3c65-a2c0-7681-a148-2904463d0447" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_019e3c65-a2c0-7f08-985f-bc8ad803bcad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e3c65-a2c0-7c1d-b97c-fd3810ef9837" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_019e3c65-a2c0-7f08-985f-bc8ad803bcad" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" xlink:href="fihl-20260630.xsd#ConsolidatedBalanceSheetsParenthetical"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7c3b-8dd7-70f3e052e827" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e3c65-a2c0-7c73-83e9-23a7b5eda7d1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7c3b-8dd7-70f3e052e827" xlink:to="loc_us-gaap_StatementTable_019e3c65-a2c0-7c73-83e9-23a7b5eda7d1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-70d6-bcb7-ab2a04300102" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e3c65-a2c0-7c73-83e9-23a7b5eda7d1" xlink:to="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-70d6-bcb7-ab2a04300102" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-70d6-bcb7-ab2a04300102_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-70d6-bcb7-ab2a04300102" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-70d6-bcb7-ab2a04300102_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7c6d-9229-a538e65bb762" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-70d6-bcb7-ab2a04300102" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7c6d-9229-a538e65bb762" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FixedMaturitiesMember_019e3c65-a2c0-7725-9269-7a45c59cf031" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FixedMaturitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7c6d-9229-a538e65bb762" xlink:to="loc_us-gaap_FixedMaturitiesMember_019e3c65-a2c0-7725-9269-7a45c59cf031" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestmentsMember_019e3c65-a2c0-7c59-b47d-e523ec99b347" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7c6d-9229-a538e65bb762" xlink:to="loc_us-gaap_ShortTermInvestmentsMember_019e3c65-a2c0-7c59-b47d-e523ec99b347" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a2c0-7374-8e4f-582d73b89d97" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e3c65-a2c0-7c73-83e9-23a7b5eda7d1" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a2c0-7374-8e4f-582d73b89d97" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e3c65-a2c0-7374-8e4f-582d73b89d97_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a2c0-7374-8e4f-582d73b89d97" xlink:to="loc_us-gaap_RelatedPartyDomain_019e3c65-a2c0-7374-8e4f-582d73b89d97_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e3c65-a2c0-7dec-9007-928f89e5e1f1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a2c0-7374-8e4f-582d73b89d97" xlink:to="loc_us-gaap_RelatedPartyDomain_019e3c65-a2c0-7dec-9007-928f89e5e1f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e3c65-a2c0-7d9b-a59b-4413e8707e30" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e3c65-a2c0-7dec-9007-928f89e5e1f1" xlink:to="loc_us-gaap_RelatedPartyMember_019e3c65-a2c0-7d9b-a59b-4413e8707e30" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss_019e3c65-a2c0-7487-9b5f-1fcd248f845c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7c3b-8dd7-70f3e052e827" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss_019e3c65-a2c0-7487-9b5f-1fcd248f845c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest_019e3c65-a2c0-7966-aee8-eb3c3b7efad1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7c3b-8dd7-70f3e052e827" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest_019e3c65-a2c0-7966-aee8-eb3c3b7efad1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PremiumsReceivableAllowanceForDoubtfulAccounts_019e3c65-a2c0-7391-9894-5cbb5e8ef126" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PremiumsReceivableAllowanceForDoubtfulAccounts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7c3b-8dd7-70f3e052e827" xlink:to="loc_us-gaap_PremiumsReceivableAllowanceForDoubtfulAccounts_019e3c65-a2c0-7391-9894-5cbb5e8ef126" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_OtherReceivablesAllowanceForCreditLoss_019e3c65-a2c0-7033-bec2-46d7d5d1efbd" xlink:href="fihl-20260630.xsd#fihl_OtherReceivablesAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7c3b-8dd7-70f3e052e827" xlink:to="loc_fihl_OtherReceivablesAllowanceForCreditLoss_019e3c65-a2c0-7033-bec2-46d7d5d1efbd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsuranceRecoverablesOnPaidLossesAllowance_019e3c65-a2c0-7beb-8549-b54e35679225" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReinsuranceRecoverablesOnPaidLossesAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7c3b-8dd7-70f3e052e827" xlink:to="loc_us-gaap_ReinsuranceRecoverablesOnPaidLossesAllowance_019e3c65-a2c0-7beb-8549-b54e35679225" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsuranceRecoverablesOnUnpaidLossesAllowance_019e3c65-a2c0-73af-b5a8-d72bf0cd1357" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReinsuranceRecoverablesOnUnpaidLossesAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7c3b-8dd7-70f3e052e827" xlink:to="loc_us-gaap_ReinsuranceRecoverablesOnUnpaidLossesAllowance_019e3c65-a2c0-73af-b5a8-d72bf0cd1357" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_DeferredPolicyAcquisitionCostDeferredCommissions_019e3c65-a2c0-74da-b66d-fb53b6f0e359" xlink:href="fihl-20260630.xsd#fihl_DeferredPolicyAcquisitionCostDeferredCommissions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7c3b-8dd7-70f3e052e827" xlink:to="loc_fihl_DeferredPolicyAcquisitionCostDeferredCommissions_019e3c65-a2c0-74da-b66d-fb53b6f0e359" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_019e3c65-a2c0-71ea-ad56-24f4a66a7a4a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7c3b-8dd7-70f3e052e827" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_019e3c65-a2c0-71ea-ad56-24f4a66a7a4a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_019e3c65-a2c0-70cd-9d92-8c3e87a10527" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7c3b-8dd7-70f3e052e827" xlink:to="loc_us-gaap_CommonStockSharesIssued_019e3c65-a2c0-70cd-9d92-8c3e87a10527" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019e3c65-a2c0-7682-8d31-ca4250cc7fcd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7c3b-8dd7-70f3e052e827" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_019e3c65-a2c0-7682-8d31-ca4250cc7fcd" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/ConsolidatedStatementsofIncomeandComprehensiveIncomeUnauditedParenthetical" xlink:type="simple" xlink:href="fihl-20260630.xsd#ConsolidatedStatementsofIncomeandComprehensiveIncomeUnauditedParenthetical"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/ConsolidatedStatementsofIncomeandComprehensiveIncomeUnauditedParenthetical" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7d6c-9a4b-b40de3d643fe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e3c65-a2c0-76a3-9593-f4b64a40d3cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7d6c-9a4b-b40de3d643fe" xlink:to="loc_us-gaap_StatementTable_019e3c65-a2c0-76a3-9593-f4b64a40d3cb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a2c0-7fd0-9b94-d5d9eeecd234" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e3c65-a2c0-76a3-9593-f4b64a40d3cb" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a2c0-7fd0-9b94-d5d9eeecd234" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e3c65-a2c0-7fd0-9b94-d5d9eeecd234_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a2c0-7fd0-9b94-d5d9eeecd234" xlink:to="loc_us-gaap_RelatedPartyDomain_019e3c65-a2c0-7fd0-9b94-d5d9eeecd234_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e3c65-a2c0-73c6-bcc5-71ede3938b5a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a2c0-7fd0-9b94-d5d9eeecd234" xlink:to="loc_us-gaap_RelatedPartyDomain_019e3c65-a2c0-73c6-bcc5-71ede3938b5a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e3c65-a2c0-743f-86fd-5cabca2899a2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e3c65-a2c0-73c6-bcc5-71ede3938b5a" xlink:to="loc_us-gaap_RelatedPartyMember_019e3c65-a2c0-743f-86fd-5cabca2899a2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_ReinsuranceCommissionExpense_019e3c65-a2c0-75c4-a42c-7a7301939aff" xlink:href="fihl-20260630.xsd#fihl_ReinsuranceCommissionExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7d6c-9a4b-b40de3d643fe" xlink:to="loc_fihl_ReinsuranceCommissionExpense_019e3c65-a2c0-75c4-a42c-7a7301939aff" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/ConsolidatedStatementsofChangesinShareholdersEquityUnaudited" xlink:type="simple" xlink:href="fihl-20260630.xsd#ConsolidatedStatementsofChangesinShareholdersEquityUnaudited"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/ConsolidatedStatementsofChangesinShareholdersEquityUnaudited" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7e93-878b-1ec5e65f89df" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e3c65-a2c0-7ad2-a25f-9a1c892c075b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7e93-878b-1ec5e65f89df" xlink:to="loc_us-gaap_StatementTable_019e3c65-a2c0-7ad2-a25f-9a1c892c075b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019e3c65-a2c0-7e8e-8981-09b46587caf0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e3c65-a2c0-7ad2-a25f-9a1c892c075b" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019e3c65-a2c0-7e8e-8981-09b46587caf0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e3c65-a2c0-7e8e-8981-09b46587caf0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e3c65-a2c0-7e8e-8981-09b46587caf0" xlink:to="loc_us-gaap_EquityComponentDomain_019e3c65-a2c0-7e8e-8981-09b46587caf0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e3c65-a2c0-73e7-8a55-f0e92ebe05b1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e3c65-a2c0-7e8e-8981-09b46587caf0" xlink:to="loc_us-gaap_EquityComponentDomain_019e3c65-a2c0-73e7-8a55-f0e92ebe05b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019e3c65-a2c0-7139-ac6f-b524c2dc7cdd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e3c65-a2c0-73e7-8a55-f0e92ebe05b1" xlink:to="loc_us-gaap_CommonStockMember_019e3c65-a2c0-7139-ac6f-b524c2dc7cdd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_019e3c65-a2c0-7c48-8ee2-8fc4b0bbde60" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockCommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e3c65-a2c0-73e7-8a55-f0e92ebe05b1" xlink:to="loc_us-gaap_TreasuryStockCommonMember_019e3c65-a2c0-7c48-8ee2-8fc4b0bbde60" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_019e3c65-a2c0-729e-a29e-3e23d89a839d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e3c65-a2c0-73e7-8a55-f0e92ebe05b1" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_019e3c65-a2c0-729e-a29e-3e23d89a839d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_019e3c65-a2c0-7d98-89f8-213e87465882" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e3c65-a2c0-73e7-8a55-f0e92ebe05b1" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_019e3c65-a2c0-7d98-89f8-213e87465882" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_019e3c65-a2c0-7f88-a206-12f50b446f27" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e3c65-a2c0-73e7-8a55-f0e92ebe05b1" xlink:to="loc_us-gaap_RetainedEarningsMember_019e3c65-a2c0-7f88-a206-12f50b446f27" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e3c65-a2c0-706a-bd56-6c7889db7ad7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e3c65-a2c0-7e93-878b-1ec5e65f89df" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e3c65-a2c0-706a-bd56-6c7889db7ad7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019e3c65-a2c0-753c-a94e-a7382474e5d7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e3c65-a2c0-706a-bd56-6c7889db7ad7" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019e3c65-a2c0-753c-a94e-a7382474e5d7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_019e3c65-a2c0-755a-a874-ac05c2424a12" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e3c65-a2c0-706a-bd56-6c7889db7ad7" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_019e3c65-a2c0-755a-a874-ac05c2424a12" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodValue_019e3c65-a2c0-7644-bdd6-6c7c4e3c53da" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchasedDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e3c65-a2c0-706a-bd56-6c7889db7ad7" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodValue_019e3c65-a2c0-7644-bdd6-6c7c4e3c53da" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockRetiredParValueMethodAmount_019e3c65-a2c0-7f25-abc2-e676a47cf8f1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockRetiredParValueMethodAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e3c65-a2c0-706a-bd56-6c7889db7ad7" xlink:to="loc_us-gaap_TreasuryStockRetiredParValueMethodAmount_019e3c65-a2c0-7f25-abc2-e676a47cf8f1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_019e3c65-a2c0-7ad3-a745-517557303c79" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e3c65-a2c0-706a-bd56-6c7889db7ad7" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_019e3c65-a2c0-7ad3-a745-517557303c79" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_019e3c65-a2c0-7945-af8e-2590ea3061f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e3c65-a2c0-706a-bd56-6c7889db7ad7" xlink:to="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_019e3c65-a2c0-7945-af8e-2590ea3061f5" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e3c65-a2c0-7b29-83cc-6cfb089ff62e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e3c65-a2c0-706a-bd56-6c7889db7ad7" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e3c65-a2c0-7b29-83cc-6cfb089ff62e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_019e3c65-a2c0-70c7-89fc-917f2a8abeb7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e3c65-a2c0-706a-bd56-6c7889db7ad7" xlink:to="loc_us-gaap_ProfitLoss_019e3c65-a2c0-70c7-89fc-917f2a8abeb7" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStock_019e3c65-a2c0-7baa-a494-c1ce175c9c0a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendsCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e3c65-a2c0-706a-bd56-6c7889db7ad7" xlink:to="loc_us-gaap_DividendsCommonStock_019e3c65-a2c0-7baa-a494-c1ce175c9c0a" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019e3c65-a2c0-7d66-aeb5-df545656a68b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/NatureofOperationsDetails" xlink:type="simple" xlink:href="fihl-20260630.xsd#NatureofOperationsDetails"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/NatureofOperationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_019e3c65-a2c0-726c-831a-788662ee3b9f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_019e3c65-a2c0-7dcc-834e-f3b24dc2bc83" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_019e3c65-a2c0-726c-831a-788662ee3b9f" xlink:to="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_019e3c65-a2c0-7dcc-834e-f3b24dc2bc83" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_019e3c65-a2c0-7263-bc80-cc11526d7be4" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_019e3c65-a2c0-7dcc-834e-f3b24dc2bc83" xlink:to="loc_srt_OwnershipAxis_019e3c65-a2c0-7263-bc80-cc11526d7be4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_019e3c65-a2c0-7263-bc80-cc11526d7be4_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_019e3c65-a2c0-7263-bc80-cc11526d7be4" xlink:to="loc_srt_OwnershipDomain_019e3c65-a2c0-7263-bc80-cc11526d7be4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_019e3c65-a2c0-7035-be4a-7480e1b65620" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_019e3c65-a2c0-7263-bc80-cc11526d7be4" xlink:to="loc_srt_OwnershipDomain_019e3c65-a2c0-7035-be4a-7480e1b65620" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_Syndicate3123Member_019e3c65-a2c0-73bd-a937-46fc10ee000a" xlink:href="fihl-20260630.xsd#fihl_Syndicate3123Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_019e3c65-a2c0-7035-be4a-7480e1b65620" xlink:to="loc_fihl_Syndicate3123Member_019e3c65-a2c0-73bd-a937-46fc10ee000a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_019e3c65-a2c0-7e29-b34a-0c02a5e978cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MinorityInterestOwnershipPercentageByParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_019e3c65-a2c0-726c-831a-788662ee3b9f" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_019e3c65-a2c0-7e29-b34a-0c02a5e978cb" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/SegmentsScheduleofGroupSegmentDisclosuresDetails" xlink:type="simple" xlink:href="fihl-20260630.xsd#SegmentsScheduleofGroupSegmentDisclosuresDetails"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/SegmentsScheduleofGroupSegmentDisclosuresDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e3c65-a2c0-7300-8abf-589a0ad3935b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e3c65-a2c0-7300-8abf-589a0ad3935b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_019e3c65-a2c0-7152-8a9f-c90dd8969174" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e3c65-a2c0-7300-8abf-589a0ad3935b" xlink:to="loc_srt_ConsolidationItemsAxis_019e3c65-a2c0-7152-8a9f-c90dd8969174" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019e3c65-a2c0-7152-8a9f-c90dd8969174_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_019e3c65-a2c0-7152-8a9f-c90dd8969174" xlink:to="loc_srt_ConsolidationItemsDomain_019e3c65-a2c0-7152-8a9f-c90dd8969174_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019e3c65-a2c0-79d6-9b1e-3b831d158974" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_019e3c65-a2c0-7152-8a9f-c90dd8969174" xlink:to="loc_srt_ConsolidationItemsDomain_019e3c65-a2c0-79d6-9b1e-3b831d158974" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_019e3c65-a2c0-7d71-b2dd-1af174a3d47c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019e3c65-a2c0-79d6-9b1e-3b831d158974" xlink:to="loc_us-gaap_OperatingSegmentsMember_019e3c65-a2c0-7d71-b2dd-1af174a3d47c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_019e3c65-a2c0-7a8b-955b-1d0f5f534da0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019e3c65-a2c0-79d6-9b1e-3b831d158974" xlink:to="loc_us-gaap_CorporateNonSegmentMember_019e3c65-a2c0-7a8b-955b-1d0f5f534da0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019e3c65-a2c0-7609-bc18-a0709a2c3c12" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e3c65-a2c0-7300-8abf-589a0ad3935b" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019e3c65-a2c0-7609-bc18-a0709a2c3c12" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e3c65-a2c0-7609-bc18-a0709a2c3c12_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e3c65-a2c0-7609-bc18-a0709a2c3c12" xlink:to="loc_us-gaap_SegmentDomain_019e3c65-a2c0-7609-bc18-a0709a2c3c12_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e3c65-a2c0-7622-9788-959681d811ab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e3c65-a2c0-7609-bc18-a0709a2c3c12" xlink:to="loc_us-gaap_SegmentDomain_019e3c65-a2c0-7622-9788-959681d811ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_SpecialtyMember_019e3c65-a2c0-7928-be1e-c1e0a5dee7c1" xlink:href="fihl-20260630.xsd#fihl_SpecialtyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e3c65-a2c0-7622-9788-959681d811ab" xlink:to="loc_fihl_SpecialtyMember_019e3c65-a2c0-7928-be1e-c1e0a5dee7c1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_ReinsuranceMember_019e3c65-a2c0-7cd2-ba08-d9d2385f1fee" xlink:href="fihl-20260630.xsd#fihl_ReinsuranceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e3c65-a2c0-7622-9788-959681d811ab" xlink:to="loc_fihl_ReinsuranceMember_019e3c65-a2c0-7cd2-ba08-d9d2385f1fee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PremiumsWrittenGross_019e3c65-a2c0-74d4-b1db-4193f8e4267a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PremiumsWrittenGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:to="loc_us-gaap_PremiumsWrittenGross_019e3c65-a2c0-74d4-b1db-4193f8e4267a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PremiumsWrittenNet_019e3c65-a2c0-7972-8600-ed2237592cce" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PremiumsWrittenNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:to="loc_us-gaap_PremiumsWrittenNet_019e3c65-a2c0-7972-8600-ed2237592cce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PremiumsEarnedNet_019e3c65-a2c0-797a-ac66-89c23955f035" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PremiumsEarnedNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:to="loc_us-gaap_PremiumsEarnedNet_019e3c65-a2c0-797a-ac66-89c23955f035" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1_019e3c65-a2c0-7ea9-a64d-557346aaa082" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:to="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1_019e3c65-a2c0-7ea9-a64d-557346aaa082" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredPolicyAcquisitionCostAmortizationExpense_019e3c65-a2c0-7e22-9f44-ba591914ea43" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredPolicyAcquisitionCostAmortizationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:to="loc_us-gaap_DeferredPolicyAcquisitionCostAmortizationExpense_019e3c65-a2c0-7e22-9f44-ba591914ea43" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_019e3c65-a2c0-71e9-bfaf-4be0e75a772d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_019e3c65-a2c0-71e9-bfaf-4be0e75a772d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnderwritingIncomeLoss_019e3c65-a2c0-70bf-a874-67e26e2ac9cd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UnderwritingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:to="loc_us-gaap_UnderwritingIncomeLoss_019e3c65-a2c0-70bf-a874-67e26e2ac9cd" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeNet_019e3c65-a2c0-769d-a5e8-d8060606af62" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentIncomeNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:to="loc_us-gaap_InvestmentIncomeNet_019e3c65-a2c0-769d-a5e8-d8060606af62" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnInvestments_019e3c65-a2c0-7f9e-ac7f-4b0f3d632a19" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:to="loc_us-gaap_GainLossOnInvestments_019e3c65-a2c0-7f9e-ac7f-4b0f3d632a19" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCostAndExpenseOperating_019e3c65-a2c0-7c7b-afbd-e5b5e543d36a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherCostAndExpenseOperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:to="loc_us-gaap_OtherCostAndExpenseOperating_019e3c65-a2c0-7c7b-afbd-e5b5e543d36a" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_019e3c65-a2c0-78f1-a503-ddd0530730b3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForeignCurrencyTransactionGainLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:to="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_019e3c65-a2c0-78f1-a503-ddd0530730b3" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfFinancingCosts_019e3c65-a2c0-7521-a788-f11d2997ffbb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AmortizationOfFinancingCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:to="loc_us-gaap_AmortizationOfFinancingCosts_019e3c65-a2c0-7521-a788-f11d2997ffbb" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e3c65-a2c0-71b4-9c94-e937f93e6ba9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e3c65-a2c0-71b4-9c94-e937f93e6ba9" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019e3c65-a2c0-7bf1-9c48-569b9d3c45e9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019e3c65-a2c0-7bf1-9c48-569b9d3c45e9" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e3c65-a2c0-75ff-b147-44cd32406748" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:to="loc_us-gaap_NetIncomeLoss_019e3c65-a2c0-75ff-b147-44cd32406748" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense_019e3c65-a2c0-7526-a1b2-515763e9786e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:to="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense_019e3c65-a2c0-7526-a1b2-515763e9786e" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense_019e3c65-a2c0-7887-832b-2c7395308262" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:to="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense_019e3c65-a2c0-7887-832b-2c7395308262" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1_019e3c65-a2c0-7254-8432-68df5a86c8c5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InsuranceRatiosAbstract_019e3c65-a2c0-7858-a453-706ddf7339bd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InsuranceRatiosAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e3c65-a2c0-7ba3-a8bd-233e445ccffa" xlink:to="loc_us-gaap_InsuranceRatiosAbstract_019e3c65-a2c0-7858-a453-706ddf7339bd" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_LossRatioCurrentYear_019e3c65-a2c0-73a1-91d9-035540e65102" xlink:href="fihl-20260630.xsd#fihl_LossRatioCurrentYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InsuranceRatiosAbstract_019e3c65-a2c0-7858-a453-706ddf7339bd" xlink:to="loc_fihl_LossRatioCurrentYear_019e3c65-a2c0-73a1-91d9-035540e65102" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_LossRatioPriorAccidentYears_019e3c65-a2c0-7964-abd1-60f5553d0b57" xlink:href="fihl-20260630.xsd#fihl_LossRatioPriorAccidentYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InsuranceRatiosAbstract_019e3c65-a2c0-7858-a453-706ddf7339bd" xlink:to="loc_fihl_LossRatioPriorAccidentYears_019e3c65-a2c0-7964-abd1-60f5553d0b57" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossRatio_019e3c65-a2c0-7cbc-ba7e-987e4811d16b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InsuranceRatiosAbstract_019e3c65-a2c0-7858-a453-706ddf7339bd" xlink:to="loc_us-gaap_LossRatio_019e3c65-a2c0-7cbc-ba7e-987e4811d16b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcquisitionCostRatio_019e3c65-a2c0-7831-b3b9-f50c99bbabda" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AcquisitionCostRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InsuranceRatiosAbstract_019e3c65-a2c0-7858-a453-706ddf7339bd" xlink:to="loc_us-gaap_AcquisitionCostRatio_019e3c65-a2c0-7831-b3b9-f50c99bbabda" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnderwritingExpenseRatio_019e3c65-a2c0-7a90-8232-d79f5f555781" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UnderwritingExpenseRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InsuranceRatiosAbstract_019e3c65-a2c0-7858-a453-706ddf7339bd" xlink:to="loc_us-gaap_UnderwritingExpenseRatio_019e3c65-a2c0-7a90-8232-d79f5f555781" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_CommissionsExpenseRatio_019e3c65-a2c0-74fb-9ff1-3905ac9d188b" xlink:href="fihl-20260630.xsd#fihl_CommissionsExpenseRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InsuranceRatiosAbstract_019e3c65-a2c0-7858-a453-706ddf7339bd" xlink:to="loc_fihl_CommissionsExpenseRatio_019e3c65-a2c0-74fb-9ff1-3905ac9d188b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpenseRatio_019e3c65-a2c0-7ddb-a6f7-35563eced433" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GeneralAndAdministrativeExpenseRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InsuranceRatiosAbstract_019e3c65-a2c0-7858-a453-706ddf7339bd" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpenseRatio_019e3c65-a2c0-7ddb-a6f7-35563eced433" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CombinedRatio_019e3c65-a2c0-7c35-a69a-ceec8f79661e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CombinedRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InsuranceRatiosAbstract_019e3c65-a2c0-7858-a453-706ddf7339bd" xlink:to="loc_us-gaap_CombinedRatio_019e3c65-a2c0-7c35-a69a-ceec8f79661e" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/InvestmentsScheduleofFairValueofInvestmentsDetails" xlink:type="simple" xlink:href="fihl-20260630.xsd#InvestmentsScheduleofFairValueofInvestmentsDetails"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/InvestmentsScheduleofFairValueofInvestmentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-7dd8-9bdf-b7dbfd3e0573" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e3c65-a2c0-715b-a692-220aa43a082e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-7dd8-9bdf-b7dbfd3e0573" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e3c65-a2c0-715b-a692-220aa43a082e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-791d-92a2-7a80a447a512" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e3c65-a2c0-715b-a692-220aa43a082e" xlink:to="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-791d-92a2-7a80a447a512" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-791d-92a2-7a80a447a512_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-791d-92a2-7a80a447a512" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-791d-92a2-7a80a447a512_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7ab7-bd47-159428349a7e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-791d-92a2-7a80a447a512" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7ab7-bd47-159428349a7e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FixedMaturitiesMember_019e3c65-a2c0-706e-abfa-f04666c54807" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FixedMaturitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7ab7-bd47-159428349a7e" xlink:to="loc_us-gaap_FixedMaturitiesMember_019e3c65-a2c0-706e-abfa-f04666c54807" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestmentsMember_019e3c65-a2c0-7535-b8ca-58b090dcc172" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7ab7-bd47-159428349a7e" xlink:to="loc_us-gaap_ShortTermInvestmentsMember_019e3c65-a2c0-7535-b8ca-58b090dcc172" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e3c65-a2c0-7c6a-9060-f490266d5be3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e3c65-a2c0-715b-a692-220aa43a082e" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e3c65-a2c0-7c6a-9060-f490266d5be3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7c6a-9060-f490266d5be3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e3c65-a2c0-7c6a-9060-f490266d5be3" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7c6a-9060-f490266d5be3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-72d6-91fc-f10697d40a28" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e3c65-a2c0-7c6a-9060-f490266d5be3" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-72d6-91fc-f10697d40a28" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_019e3c65-a2c0-7160-b2a5-a60c819eda2c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-72d6-91fc-f10697d40a28" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_019e3c65-a2c0-7160-b2a5-a60c819eda2c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AgencySecuritiesMember_019e3c65-a2c0-7ba4-927c-c4b22f13d217" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AgencySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-72d6-91fc-f10697d40a28" xlink:to="loc_us-gaap_AgencySecuritiesMember_019e3c65-a2c0-7ba4-927c-c4b22f13d217" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignGovernmentDebtSecuritiesMember_019e3c65-a2c0-7359-a5d5-ba119d27c11d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForeignGovernmentDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-72d6-91fc-f10697d40a28" xlink:to="loc_us-gaap_ForeignGovernmentDebtSecuritiesMember_019e3c65-a2c0-7359-a5d5-ba119d27c11d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_019e3c65-a2c0-7c29-a983-5f2c756a90f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-72d6-91fc-f10697d40a28" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_019e3c65-a2c0-7c29-a983-5f2c756a90f5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_019e3c65-a2c0-70d7-bcd8-94e22c8fb2eb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-72d6-91fc-f10697d40a28" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_019e3c65-a2c0-70d7-bcd8-94e22c8fb2eb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_019e3c65-a2c0-76e7-9588-c0949f1a0bac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-72d6-91fc-f10697d40a28" xlink:to="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_019e3c65-a2c0-76e7-9588-c0949f1a0bac" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_019e3c65-a2c0-78d1-881a-516aba57f285" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-72d6-91fc-f10697d40a28" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_019e3c65-a2c0-78d1-881a-516aba57f285" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss_019e3c65-a2c0-7dfa-8ffe-0341017017c5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-7dd8-9bdf-b7dbfd3e0573" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss_019e3c65-a2c0-7dfa-8ffe-0341017017c5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_019e3c65-a2c0-75ba-9445-3550d7aacdea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-7dd8-9bdf-b7dbfd3e0573" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_019e3c65-a2c0-75ba-9445-3550d7aacdea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_019e3c65-a2c0-7772-8e42-054cde277f0c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-7dd8-9bdf-b7dbfd3e0573" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_019e3c65-a2c0-7772-8e42-054cde277f0c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e3c65-a2c0-79cc-8c8e-b7fec86a447b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-7dd8-9bdf-b7dbfd3e0573" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e3c65-a2c0-79cc-8c8e-b7fec86a447b" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/InvestmentsScheduleofCompositionoftheFairValuesofInvestmentsbyCreditRatingDetails" xlink:type="simple" xlink:href="fihl-20260630.xsd#InvestmentsScheduleofCompositionoftheFairValuesofInvestmentsbyCreditRatingDetails"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/InvestmentsScheduleofCompositionoftheFairValuesofInvestmentsbyCreditRatingDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorLineItems_019e3c65-a2c0-7680-adef-cb8255aa6f0a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorTable_019e3c65-a2c0-73c4-ba66-1d4f268f1203" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorLineItems_019e3c65-a2c0-7680-adef-cb8255aa6f0a" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorTable_019e3c65-a2c0-73c4-ba66-1d4f268f1203" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_CreditRatingAxis_019e3c65-a2c0-79dd-a8be-3209c8cb7ec3" xlink:href="fihl-20260630.xsd#fihl_CreditRatingAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorTable_019e3c65-a2c0-73c4-ba66-1d4f268f1203" xlink:to="loc_fihl_CreditRatingAxis_019e3c65-a2c0-79dd-a8be-3209c8cb7ec3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_CreditRatingDomain_019e3c65-a2c0-79dd-a8be-3209c8cb7ec3_default" xlink:href="fihl-20260630.xsd#fihl_CreditRatingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_fihl_CreditRatingAxis_019e3c65-a2c0-79dd-a8be-3209c8cb7ec3" xlink:to="loc_fihl_CreditRatingDomain_019e3c65-a2c0-79dd-a8be-3209c8cb7ec3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_CreditRatingDomain_019e3c65-a2c0-7e57-8bc4-1d2064e027f9" xlink:href="fihl-20260630.xsd#fihl_CreditRatingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_fihl_CreditRatingAxis_019e3c65-a2c0-79dd-a8be-3209c8cb7ec3" xlink:to="loc_fihl_CreditRatingDomain_019e3c65-a2c0-7e57-8bc4-1d2064e027f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_AAAMember_019e3c65-a2c0-78a3-8642-12decd330c89" xlink:href="fihl-20260630.xsd#fihl_AAAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_fihl_CreditRatingDomain_019e3c65-a2c0-7e57-8bc4-1d2064e027f9" xlink:to="loc_fihl_AAAMember_019e3c65-a2c0-78a3-8642-12decd330c89" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_AAMember_019e3c65-a2c0-79f7-b5e6-6f535330f60d" xlink:href="fihl-20260630.xsd#fihl_AAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_fihl_CreditRatingDomain_019e3c65-a2c0-7e57-8bc4-1d2064e027f9" xlink:to="loc_fihl_AAMember_019e3c65-a2c0-79f7-b5e6-6f535330f60d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_AMember_019e3c65-a2c0-7853-bbfd-7cd9502e405a" xlink:href="fihl-20260630.xsd#fihl_AMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_fihl_CreditRatingDomain_019e3c65-a2c0-7e57-8bc4-1d2064e027f9" xlink:to="loc_fihl_AMember_019e3c65-a2c0-7853-bbfd-7cd9502e405a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_BBBMember_019e3c65-a2c0-7bb0-8b5d-ca46686081e0" xlink:href="fihl-20260630.xsd#fihl_BBBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_fihl_CreditRatingDomain_019e3c65-a2c0-7e57-8bc4-1d2064e027f9" xlink:to="loc_fihl_BBBMember_019e3c65-a2c0-7bb0-8b5d-ca46686081e0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_BelowBBBMember_019e3c65-a2c0-7336-a438-08cd03ae187f" xlink:href="fihl-20260630.xsd#fihl_BelowBBBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_fihl_CreditRatingDomain_019e3c65-a2c0-7e57-8bc4-1d2064e027f9" xlink:to="loc_fihl_BelowBBBMember_019e3c65-a2c0-7336-a438-08cd03ae187f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-7a26-9f01-16fc22217802" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorTable_019e3c65-a2c0-73c4-ba66-1d4f268f1203" xlink:to="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-7a26-9f01-16fc22217802" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7a26-9f01-16fc22217802_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-7a26-9f01-16fc22217802" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7a26-9f01-16fc22217802_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7aee-ae3c-6a0a05a9baa7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-7a26-9f01-16fc22217802" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7aee-ae3c-6a0a05a9baa7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FixedMaturitiesMember_019e3c65-a2c0-7857-b00a-3d7360e9ecca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FixedMaturitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7aee-ae3c-6a0a05a9baa7" xlink:to="loc_us-gaap_FixedMaturitiesMember_019e3c65-a2c0-7857-b00a-3d7360e9ecca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestmentsMember_019e3c65-a2c0-790d-8374-df8868d3c5c5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7aee-ae3c-6a0a05a9baa7" xlink:to="loc_us-gaap_ShortTermInvestmentsMember_019e3c65-a2c0-790d-8374-df8868d3c5c5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e3c65-a2c0-7072-92b6-3b2443701956" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorTable_019e3c65-a2c0-73c4-ba66-1d4f268f1203" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e3c65-a2c0-7072-92b6-3b2443701956" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e3c65-a2c0-7072-92b6-3b2443701956_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e3c65-a2c0-7072-92b6-3b2443701956" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e3c65-a2c0-7072-92b6-3b2443701956_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e3c65-a2c0-7595-b13f-2621413f6637" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e3c65-a2c0-7072-92b6-3b2443701956" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e3c65-a2c0-7595-b13f-2621413f6637" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_CreditRatingMember_019e3c65-a2c0-7b93-8c4d-30fabcc2586f" xlink:href="fihl-20260630.xsd#fihl_CreditRatingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e3c65-a2c0-7595-b13f-2621413f6637" xlink:to="loc_fihl_CreditRatingMember_019e3c65-a2c0-7b93-8c4d-30fabcc2586f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_019e3c65-a2c0-7fd3-98c7-e3d9f63ed578" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorTable_019e3c65-a2c0-73c4-ba66-1d4f268f1203" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_019e3c65-a2c0-7fd3-98c7-e3d9f63ed578" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_019e3c65-a2c0-7fd3-98c7-e3d9f63ed578_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_019e3c65-a2c0-7fd3-98c7-e3d9f63ed578" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_019e3c65-a2c0-7fd3-98c7-e3d9f63ed578_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_019e3c65-a2c0-7976-8f95-caa386896035" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_019e3c65-a2c0-7fd3-98c7-e3d9f63ed578" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_019e3c65-a2c0-7976-8f95-caa386896035" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditConcentrationRiskMember_019e3c65-a2c0-7733-863f-862c11c4a6a6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_019e3c65-a2c0-7976-8f95-caa386896035" xlink:to="loc_us-gaap_CreditConcentrationRiskMember_019e3c65-a2c0-7733-863f-862c11c4a6a6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e3c65-a2c0-7305-a71e-8e2266259a8e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorLineItems_019e3c65-a2c0-7680-adef-cb8255aa6f0a" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e3c65-a2c0-7305-a71e-8e2266259a8e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_019e3c65-a2c0-7675-9b74-dbfb4004ec9d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityCreditQualityIndicatorLineItems_019e3c65-a2c0-7680-adef-cb8255aa6f0a" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_019e3c65-a2c0-7675-9b74-dbfb4004ec9d" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/InvestmentsScheduleofContinuousLossPositionDetails" xlink:type="simple" xlink:href="fihl-20260630.xsd#InvestmentsScheduleofContinuousLossPositionDetails"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/InvestmentsScheduleofContinuousLossPositionDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-786f-9cfe-26297c9c54e5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e3c65-a2c0-7849-a5d3-7164dddeba7d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-786f-9cfe-26297c9c54e5" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e3c65-a2c0-7849-a5d3-7164dddeba7d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e3c65-a2c0-7bf9-95be-f680b867bd63" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e3c65-a2c0-7849-a5d3-7164dddeba7d" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e3c65-a2c0-7bf9-95be-f680b867bd63" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7bf9-95be-f680b867bd63_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e3c65-a2c0-7bf9-95be-f680b867bd63" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7bf9-95be-f680b867bd63_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7c8e-9032-ee4fdb1e0886" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e3c65-a2c0-7bf9-95be-f680b867bd63" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7c8e-9032-ee4fdb1e0886" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_019e3c65-a2c0-7136-8f51-5981411a2188" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7c8e-9032-ee4fdb1e0886" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_019e3c65-a2c0-7136-8f51-5981411a2188" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignGovernmentDebtSecuritiesMember_019e3c65-a2c0-7fd0-b45b-76b4e9d2ce25" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForeignGovernmentDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7c8e-9032-ee4fdb1e0886" xlink:to="loc_us-gaap_ForeignGovernmentDebtSecuritiesMember_019e3c65-a2c0-7fd0-b45b-76b4e9d2ce25" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_019e3c65-a2c0-7695-a0cf-265ae458bf72" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7c8e-9032-ee4fdb1e0886" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_019e3c65-a2c0-7695-a0cf-265ae458bf72" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_019e3c65-a2c0-7e13-b82b-b25107033e31" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7c8e-9032-ee4fdb1e0886" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_019e3c65-a2c0-7e13-b82b-b25107033e31" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_019e3c65-a2c0-7921-8d47-93c794239b1b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7c8e-9032-ee4fdb1e0886" xlink:to="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_019e3c65-a2c0-7921-8d47-93c794239b1b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_019e3c65-a2c0-7fe6-bac1-b1db396c794c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7c8e-9032-ee4fdb1e0886" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_019e3c65-a2c0-7fe6-bac1-b1db396c794c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_019e3c65-a2c0-7767-9285-ab92d01f2515" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-786f-9cfe-26297c9c54e5" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_019e3c65-a2c0-7767-9285-ab92d01f2515" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_019e3c65-a2c0-7d4a-aa71-6532a15a2062" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-786f-9cfe-26297c9c54e5" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_019e3c65-a2c0-7d4a-aa71-6532a15a2062" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_019e3c65-a2c0-70b4-a566-68da8052f552" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-786f-9cfe-26297c9c54e5" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_019e3c65-a2c0-70b4-a566-68da8052f552" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions_019e3c65-a2c0-7fc5-81aa-5cab8ba3b204" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-786f-9cfe-26297c9c54e5" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions_019e3c65-a2c0-7fc5-81aa-5cab8ba3b204" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/InvestmentsNarrativeDetails" xlink:type="simple" xlink:href="fihl-20260630.xsd#InvestmentsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/InvestmentsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-7342-bb67-b528ed1a5d9b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e3c65-a2c0-7ed6-866d-41e69e5ccf99" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-7342-bb67-b528ed1a5d9b" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e3c65-a2c0-7ed6-866d-41e69e5ccf99" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019e3c65-a2c0-7a01-90f6-8b1861df4083" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e3c65-a2c0-7ed6-866d-41e69e5ccf99" xlink:to="loc_srt_RangeAxis_019e3c65-a2c0-7a01-90f6-8b1861df4083" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e3c65-a2c0-7a01-90f6-8b1861df4083_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019e3c65-a2c0-7a01-90f6-8b1861df4083" xlink:to="loc_srt_RangeMember_019e3c65-a2c0-7a01-90f6-8b1861df4083_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e3c65-a2c0-7b38-bf89-bf3d88916210" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019e3c65-a2c0-7a01-90f6-8b1861df4083" xlink:to="loc_srt_RangeMember_019e3c65-a2c0-7b38-bf89-bf3d88916210" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019e3c65-a2c0-724c-806b-b9610b5125ce" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e3c65-a2c0-7b38-bf89-bf3d88916210" xlink:to="loc_srt_MinimumMember_019e3c65-a2c0-724c-806b-b9610b5125ce" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019e3c65-a2c0-71e3-b7f8-a0d529650b2f" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e3c65-a2c0-7b38-bf89-bf3d88916210" xlink:to="loc_srt_MaximumMember_019e3c65-a2c0-71e3-b7f8-a0d529650b2f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_InvestmentStrategyAxis_019e3c65-a2c0-7dee-8b64-693f3af611fe" xlink:href="fihl-20260630.xsd#fihl_InvestmentStrategyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e3c65-a2c0-7ed6-866d-41e69e5ccf99" xlink:to="loc_fihl_InvestmentStrategyAxis_019e3c65-a2c0-7dee-8b64-693f3af611fe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_InvestmentStrategyDomain_019e3c65-a2c0-7dee-8b64-693f3af611fe_default" xlink:href="fihl-20260630.xsd#fihl_InvestmentStrategyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_fihl_InvestmentStrategyAxis_019e3c65-a2c0-7dee-8b64-693f3af611fe" xlink:to="loc_fihl_InvestmentStrategyDomain_019e3c65-a2c0-7dee-8b64-693f3af611fe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_InvestmentStrategyDomain_019e3c65-a2c0-7f29-93d3-bf45453ec0d8" xlink:href="fihl-20260630.xsd#fihl_InvestmentStrategyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_fihl_InvestmentStrategyAxis_019e3c65-a2c0-7dee-8b64-693f3af611fe" xlink:to="loc_fihl_InvestmentStrategyDomain_019e3c65-a2c0-7f29-93d3-bf45453ec0d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_PrivateCreditFundsMember_019e3c65-a2c0-735e-a698-2022bd30c350" xlink:href="fihl-20260630.xsd#fihl_PrivateCreditFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_fihl_InvestmentStrategyDomain_019e3c65-a2c0-7f29-93d3-bf45453ec0d8" xlink:to="loc_fihl_PrivateCreditFundsMember_019e3c65-a2c0-735e-a698-2022bd30c350" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions_019e3c65-a2c0-7984-8ef2-53d33b722aa6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-7342-bb67-b528ed1a5d9b" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions_019e3c65-a2c0-7984-8ef2-53d33b722aa6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_DebtSecuritiesAvailableForSaleNumberOfPositions_019e3c65-a2c0-7e70-adb1-2b8d14723719" xlink:href="fihl-20260630.xsd#fihl_DebtSecuritiesAvailableForSaleNumberOfPositions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-7342-bb67-b528ed1a5d9b" xlink:to="loc_fihl_DebtSecuritiesAvailableForSaleNumberOfPositions_019e3c65-a2c0-7e70-adb1-2b8d14723719" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLargestSingleAmount_019e3c65-a2c0-7121-b2c0-a827222b4ad3" xlink:href="fihl-20260630.xsd#fihl_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLargestSingleAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-7342-bb67-b528ed1a5d9b" xlink:to="loc_fihl_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLargestSingleAmount_019e3c65-a2c0-7121-b2c0-a827222b4ad3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AlternativeInvestment_019e3c65-a2c0-790e-875c-e8baa1ef84bd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AlternativeInvestment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-7342-bb67-b528ed1a5d9b" xlink:to="loc_us-gaap_AlternativeInvestment_019e3c65-a2c0-790e-875c-e8baa1ef84bd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments_019e3c65-a2c0-71f6-a8ef-eee105dc3815" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-7342-bb67-b528ed1a5d9b" xlink:to="loc_us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments_019e3c65-a2c0-71f6-a8ef-eee105dc3815" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_PercentageOfTotalNetAssetValueOfHedgeFund_019e3c65-a2c0-7e45-b440-daa79ac819b4" xlink:href="fihl-20260630.xsd#fihl_PercentageOfTotalNetAssetValueOfHedgeFund"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-7342-bb67-b528ed1a5d9b" xlink:to="loc_fihl_PercentageOfTotalNetAssetValueOfHedgeFund_019e3c65-a2c0-7e45-b440-daa79ac819b4" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/InvestmentsScheduleofOtherInvestmentsatFairValueDetails" xlink:type="simple" xlink:href="fihl-20260630.xsd#InvestmentsScheduleofOtherInvestmentsatFairValueDetails"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/InvestmentsScheduleofOtherInvestmentsatFairValueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-7f33-b68e-93d2e0b298c4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e3c65-a2c0-7ca2-b5b9-fc1a9aa64fcf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-7f33-b68e-93d2e0b298c4" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e3c65-a2c0-7ca2-b5b9-fc1a9aa64fcf" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_InvestmentStrategyAxis_019e3c65-a2c0-7859-9384-0dea02a76322" xlink:href="fihl-20260630.xsd#fihl_InvestmentStrategyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e3c65-a2c0-7ca2-b5b9-fc1a9aa64fcf" xlink:to="loc_fihl_InvestmentStrategyAxis_019e3c65-a2c0-7859-9384-0dea02a76322" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_InvestmentStrategyDomain_019e3c65-a2c0-7859-9384-0dea02a76322_default" xlink:href="fihl-20260630.xsd#fihl_InvestmentStrategyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_fihl_InvestmentStrategyAxis_019e3c65-a2c0-7859-9384-0dea02a76322" xlink:to="loc_fihl_InvestmentStrategyDomain_019e3c65-a2c0-7859-9384-0dea02a76322_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_InvestmentStrategyDomain_019e3c65-a2c0-73b8-9d7e-364fa24e33f1" xlink:href="fihl-20260630.xsd#fihl_InvestmentStrategyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_fihl_InvestmentStrategyAxis_019e3c65-a2c0-7859-9384-0dea02a76322" xlink:to="loc_fihl_InvestmentStrategyDomain_019e3c65-a2c0-73b8-9d7e-364fa24e33f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_MultiAssetCreditFundsMember_019e3c65-a2c0-7402-9f8f-5fa5a9df6629" xlink:href="fihl-20260630.xsd#fihl_MultiAssetCreditFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_fihl_InvestmentStrategyDomain_019e3c65-a2c0-73b8-9d7e-364fa24e33f1" xlink:to="loc_fihl_MultiAssetCreditFundsMember_019e3c65-a2c0-7402-9f8f-5fa5a9df6629" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditMember_019e3c65-a2c0-7bc4-bd95-31e7bc3f5992" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_fihl_InvestmentStrategyDomain_019e3c65-a2c0-73b8-9d7e-364fa24e33f1" xlink:to="loc_us-gaap_CreditMember_019e3c65-a2c0-7bc4-bd95-31e7bc3f5992" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_GlobalMacroMember_019e3c65-a2c0-7286-b0d6-d04312d8aa63" xlink:href="fihl-20260630.xsd#fihl_GlobalMacroMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_fihl_InvestmentStrategyDomain_019e3c65-a2c0-73b8-9d7e-364fa24e33f1" xlink:to="loc_fihl_GlobalMacroMember_019e3c65-a2c0-7286-b0d6-d04312d8aa63" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_LongShortMember_019e3c65-a2c0-7bfb-9cd7-648e752d51ba" xlink:href="fihl-20260630.xsd#fihl_LongShortMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_fihl_InvestmentStrategyDomain_019e3c65-a2c0-73b8-9d7e-364fa24e33f1" xlink:to="loc_fihl_LongShortMember_019e3c65-a2c0-7bfb-9cd7-648e752d51ba" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_MultiStrategyAndEventDrivenMember_019e3c65-a2c0-7444-94b9-704d4604d3ac" xlink:href="fihl-20260630.xsd#fihl_MultiStrategyAndEventDrivenMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_fihl_InvestmentStrategyDomain_019e3c65-a2c0-73b8-9d7e-364fa24e33f1" xlink:to="loc_fihl_MultiStrategyAndEventDrivenMember_019e3c65-a2c0-7444-94b9-704d4604d3ac" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_PrivateCreditFundsMember_019e3c65-a2c0-7413-a8a8-f425287e3286" xlink:href="fihl-20260630.xsd#fihl_PrivateCreditFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_fihl_InvestmentStrategyDomain_019e3c65-a2c0-73b8-9d7e-364fa24e33f1" xlink:to="loc_fihl_PrivateCreditFundsMember_019e3c65-a2c0-7413-a8a8-f425287e3286" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e3c65-a2c0-7651-88d2-78654328a791" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e3c65-a2c0-7ca2-b5b9-fc1a9aa64fcf" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e3c65-a2c0-7651-88d2-78654328a791" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e3c65-a2c0-7651-88d2-78654328a791_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e3c65-a2c0-7651-88d2-78654328a791" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e3c65-a2c0-7651-88d2-78654328a791_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e3c65-a2c0-7ab7-889c-050275d770e9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e3c65-a2c0-7651-88d2-78654328a791" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e3c65-a2c0-7ab7-889c-050275d770e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_CreditRatingMember_019e3c65-a2c0-7533-a5af-355a2bd96136" xlink:href="fihl-20260630.xsd#fihl_CreditRatingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e3c65-a2c0-7ab7-889c-050275d770e9" xlink:to="loc_fihl_CreditRatingMember_019e3c65-a2c0-7533-a5af-355a2bd96136" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_019e3c65-a2c0-774d-898f-06df64cfda78" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e3c65-a2c0-7ca2-b5b9-fc1a9aa64fcf" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_019e3c65-a2c0-774d-898f-06df64cfda78" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_019e3c65-a2c0-774d-898f-06df64cfda78_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_019e3c65-a2c0-774d-898f-06df64cfda78" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_019e3c65-a2c0-774d-898f-06df64cfda78_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_019e3c65-a2c0-7f5d-9136-24f1ed332e95" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_019e3c65-a2c0-774d-898f-06df64cfda78" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_019e3c65-a2c0-7f5d-9136-24f1ed332e95" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditConcentrationRiskMember_019e3c65-a2c0-756d-a952-6c9d7ebbd80e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_019e3c65-a2c0-7f5d-9136-24f1ed332e95" xlink:to="loc_us-gaap_CreditConcentrationRiskMember_019e3c65-a2c0-756d-a952-6c9d7ebbd80e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIssuerNameAxis_019e3c65-a2c0-774c-a18d-deb1cb58b8ec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentIssuerNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019e3c65-a2c0-7ca2-b5b9-fc1a9aa64fcf" xlink:to="loc_us-gaap_InvestmentIssuerNameAxis_019e3c65-a2c0-774c-a18d-deb1cb58b8ec" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIssuerNameDomain_019e3c65-a2c0-774c-a18d-deb1cb58b8ec_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentIssuerNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentIssuerNameAxis_019e3c65-a2c0-774c-a18d-deb1cb58b8ec" xlink:to="loc_us-gaap_InvestmentIssuerNameDomain_019e3c65-a2c0-774c-a18d-deb1cb58b8ec_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIssuerNameDomain_019e3c65-a2c0-7a31-a8d6-1a177ddee2aa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentIssuerNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentIssuerNameAxis_019e3c65-a2c0-774c-a18d-deb1cb58b8ec" xlink:to="loc_us-gaap_InvestmentIssuerNameDomain_019e3c65-a2c0-7a31-a8d6-1a177ddee2aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_HedgeFundInvestmentsMember_019e3c65-a2c0-72c1-b642-32ad2baac8e4" xlink:href="fihl-20260630.xsd#fihl_HedgeFundInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentIssuerNameDomain_019e3c65-a2c0-7a31-a8d6-1a177ddee2aa" xlink:to="loc_fihl_HedgeFundInvestmentsMember_019e3c65-a2c0-72c1-b642-32ad2baac8e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLongTermInvestments_019e3c65-a2c0-7e28-a37b-f6c7f7b6f037" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLongTermInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-7f33-b68e-93d2e0b298c4" xlink:to="loc_us-gaap_OtherLongTermInvestments_019e3c65-a2c0-7e28-a37b-f6c7f7b6f037" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_019e3c65-a2c0-71c6-9bed-608fa652a133" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019e3c65-a2c0-7f33-b68e-93d2e0b298c4" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_019e3c65-a2c0-71c6-9bed-608fa652a133" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/FairValueMeasurementsScheduleofFinancialInstrumentsMeasuredatFairValueonaRecurringBasisDetails" xlink:type="simple" xlink:href="fihl-20260630.xsd#FairValueMeasurementsScheduleofFinancialInstrumentsMeasuredatFairValueonaRecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/FairValueMeasurementsScheduleofFinancialInstrumentsMeasuredatFairValueonaRecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureAssetAndLiabilityNotMeasuredAtFairValueLineItems_019e3c65-a2c0-7f3b-b1f7-11f902fc154d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueDisclosureAssetAndLiabilityNotMeasuredAtFairValueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable_019e3c65-a2c0-7f58-8a99-7351cc6c1ff9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueDisclosureAssetAndLiabilityNotMeasuredAtFairValueLineItems_019e3c65-a2c0-7f3b-b1f7-11f902fc154d" xlink:to="loc_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable_019e3c65-a2c0-7f58-8a99-7351cc6c1ff9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e3c65-a2c0-7c5e-9182-18198cc277cc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable_019e3c65-a2c0-7f58-8a99-7351cc6c1ff9" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e3c65-a2c0-7c5e-9182-18198cc277cc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e3c65-a2c0-7c5e-9182-18198cc277cc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e3c65-a2c0-7c5e-9182-18198cc277cc" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e3c65-a2c0-7c5e-9182-18198cc277cc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e3c65-a2c0-7ee3-9d4b-76b659b7f750" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e3c65-a2c0-7c5e-9182-18198cc277cc" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e3c65-a2c0-7ee3-9d4b-76b659b7f750" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_019e3c65-a2c0-781c-9b50-6c4e052e85ae" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e3c65-a2c0-7ee3-9d4b-76b659b7f750" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_019e3c65-a2c0-781c-9b50-6c4e052e85ae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_019e3c65-a2c0-7365-b5ca-5d7638bcf1c4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e3c65-a2c0-7ee3-9d4b-76b659b7f750" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_019e3c65-a2c0-7365-b5ca-5d7638bcf1c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019e3c65-a2c0-7868-97bd-a29ce465c3a1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e3c65-a2c0-7ee3-9d4b-76b659b7f750" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019e3c65-a2c0-7868-97bd-a29ce465c3a1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-76bb-a806-98fa63f5106a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable_019e3c65-a2c0-7f58-8a99-7351cc6c1ff9" xlink:to="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-76bb-a806-98fa63f5106a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-76bb-a806-98fa63f5106a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-76bb-a806-98fa63f5106a" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-76bb-a806-98fa63f5106a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7c4b-ae9b-faace89925a0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_019e3c65-a2c0-76bb-a806-98fa63f5106a" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7c4b-ae9b-faace89925a0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FixedMaturitiesMember_019e3c65-a2c0-78c0-98a0-4fe83e5b6b51" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FixedMaturitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7c4b-ae9b-faace89925a0" xlink:to="loc_us-gaap_FixedMaturitiesMember_019e3c65-a2c0-78c0-98a0-4fe83e5b6b51" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestmentsMember_019e3c65-a2c0-7cbf-9d2f-d5529e7603a1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019e3c65-a2c0-7c4b-ae9b-faace89925a0" xlink:to="loc_us-gaap_ShortTermInvestmentsMember_019e3c65-a2c0-7cbf-9d2f-d5529e7603a1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e3c65-a2c0-72f7-a886-8d6f83f77f21" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable_019e3c65-a2c0-7f58-8a99-7351cc6c1ff9" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e3c65-a2c0-72f7-a886-8d6f83f77f21" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-72f7-a886-8d6f83f77f21_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e3c65-a2c0-72f7-a886-8d6f83f77f21" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-72f7-a886-8d6f83f77f21_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7662-b335-6bd837b8bc2c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e3c65-a2c0-72f7-a886-8d6f83f77f21" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7662-b335-6bd837b8bc2c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_019e3c65-a2c0-70f4-9bfe-ee20849abf82" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7662-b335-6bd837b8bc2c" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_019e3c65-a2c0-70f4-9bfe-ee20849abf82" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AgencySecuritiesMember_019e3c65-a2c0-7b98-ba3c-a4d14af16e0d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AgencySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7662-b335-6bd837b8bc2c" xlink:to="loc_us-gaap_AgencySecuritiesMember_019e3c65-a2c0-7b98-ba3c-a4d14af16e0d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignGovernmentDebtSecuritiesMember_019e3c65-a2c0-7d7d-ae68-de25eae5ec18" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForeignGovernmentDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7662-b335-6bd837b8bc2c" xlink:to="loc_us-gaap_ForeignGovernmentDebtSecuritiesMember_019e3c65-a2c0-7d7d-ae68-de25eae5ec18" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_019e3c65-a2c0-7887-b43e-63d8493f3265" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7662-b335-6bd837b8bc2c" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_019e3c65-a2c0-7887-b43e-63d8493f3265" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_019e3c65-a2c0-79b5-a11f-39a7e4ece59a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7662-b335-6bd837b8bc2c" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_019e3c65-a2c0-79b5-a11f-39a7e4ece59a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_019e3c65-a2c0-7033-a547-9cfbe07c0a4b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7662-b335-6bd837b8bc2c" xlink:to="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_019e3c65-a2c0-7033-a547-9cfbe07c0a4b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_019e3c65-a2c0-7c58-b144-ebfdb8946cc8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e3c65-a2c0-7662-b335-6bd837b8bc2c" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_019e3c65-a2c0-7c58-b144-ebfdb8946cc8" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosureAbstract_019e3c65-a2c0-782b-9886-0c8ced373871" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureAssetAndLiabilityNotMeasuredAtFairValueLineItems_019e3c65-a2c0-7f3b-b1f7-11f902fc154d" xlink:to="loc_us-gaap_AssetsFairValueDisclosureAbstract_019e3c65-a2c0-782b-9886-0c8ced373871" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e3c65-a2c0-7eb5-87a0-278ba8ea70e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_019e3c65-a2c0-782b-9886-0c8ced373871" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e3c65-a2c0-7eb5-87a0-278ba8ea70e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_AssetsInvestmentsPendingSettlementFairValueDisclosure_019e3c65-a2c0-7039-b677-daa35191fb54" xlink:href="fihl-20260630.xsd#fihl_AssetsInvestmentsPendingSettlementFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_019e3c65-a2c0-782b-9886-0c8ced373871" xlink:to="loc_fihl_AssetsInvestmentsPendingSettlementFairValueDisclosure_019e3c65-a2c0-7039-b677-daa35191fb54" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_019e3c65-a2c0-7b50-a325-c491ee804f02" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_019e3c65-a2c0-782b-9886-0c8ced373871" xlink:to="loc_us-gaap_DerivativeAssets_019e3c65-a2c0-7b50-a325-c491ee804f02" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsFairValueDisclosure_019e3c65-a2c0-7921-8d79-d465fddc09ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_019e3c65-a2c0-782b-9886-0c8ced373871" xlink:to="loc_us-gaap_OtherAssetsFairValueDisclosure_019e3c65-a2c0-7921-8d79-d465fddc09ca" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_019e3c65-a2c0-7923-b044-8a6911f0d523" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_019e3c65-a2c0-782b-9886-0c8ced373871" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_019e3c65-a2c0-7923-b044-8a6911f0d523" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_019e3c65-a2c0-7138-b67b-cffc1ce5cc5e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureAssetAndLiabilityNotMeasuredAtFairValueLineItems_019e3c65-a2c0-7f3b-b1f7-11f902fc154d" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_019e3c65-a2c0-7138-b67b-cffc1ce5cc5e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_LiabilitiesInvestmentsPendingSettlementFairValueDisclosure_019e3c65-a2c0-7d3a-830a-3befa1d4045e" xlink:href="fihl-20260630.xsd#fihl_LiabilitiesInvestmentsPendingSettlementFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_019e3c65-a2c0-7138-b67b-cffc1ce5cc5e" xlink:to="loc_fihl_LiabilitiesInvestmentsPendingSettlementFairValueDisclosure_019e3c65-a2c0-7d3a-830a-3befa1d4045e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities_019e3c65-a2c0-7481-b839-8121aa8ce07c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_019e3c65-a2c0-7138-b67b-cffc1ce5cc5e" xlink:to="loc_us-gaap_DerivativeLiabilities_019e3c65-a2c0-7481-b839-8121aa8ce07c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesFairValueDisclosure_019e3c65-a2c0-7985-8c00-0fdaff9b48d5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_019e3c65-a2c0-7138-b67b-cffc1ce5cc5e" xlink:to="loc_us-gaap_OtherLiabilitiesFairValueDisclosure_019e3c65-a2c0-7985-8c00-0fdaff9b48d5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_019e3c65-a2c0-7650-a4c9-79202404515e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_019e3c65-a2c0-7138-b67b-cffc1ce5cc5e" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_019e3c65-a2c0-7650-a4c9-79202404515e" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/FairValueMeasurementsScheduleofFinancialInstrumentsBasedonObservableInputsDetails" xlink:type="simple" xlink:href="fihl-20260630.xsd#FairValueMeasurementsScheduleofFinancialInstrumentsBasedonObservableInputsDetails"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/FairValueMeasurementsScheduleofFinancialInstrumentsBasedonObservableInputsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureAssetAndLiabilityNotMeasuredAtFairValueLineItems_019e3c65-a2c0-7010-acfd-469a889df88b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueDisclosureAssetAndLiabilityNotMeasuredAtFairValueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable_019e3c65-a2c0-77a9-b155-385b623c1ac7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueDisclosureAssetAndLiabilityNotMeasuredAtFairValueLineItems_019e3c65-a2c0-7010-acfd-469a889df88b" xlink:to="loc_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable_019e3c65-a2c0-77a9-b155-385b623c1ac7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_019e3c65-a2c0-7e84-8201-2d1eb4de47af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable_019e3c65-a2c0-77a9-b155-385b623c1ac7" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_019e3c65-a2c0-7e84-8201-2d1eb4de47af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019e3c65-a2c0-7e84-8201-2d1eb4de47af_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_019e3c65-a2c0-7e84-8201-2d1eb4de47af" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019e3c65-a2c0-7e84-8201-2d1eb4de47af_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019e3c65-a2c0-7348-9700-b7730996042a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_019e3c65-a2c0-7e84-8201-2d1eb4de47af" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019e3c65-a2c0-7348-9700-b7730996042a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019e3c65-a2c0-7d0b-b1e7-088de2595ac1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019e3c65-a2c0-7348-9700-b7730996042a" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019e3c65-a2c0-7d0b-b1e7-088de2595ac1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_019e3c65-a2c0-7b26-b626-94d28741e030" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019e3c65-a2c0-7d0b-b1e7-088de2595ac1" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_019e3c65-a2c0-7b26-b626-94d28741e030" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_019e3c65-a2c0-7268-aa8e-2773f233aeec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019e3c65-a2c0-7d0b-b1e7-088de2595ac1" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_019e3c65-a2c0-7268-aa8e-2773f233aeec" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019e3c65-a2c0-7698-8fba-6030709d6616" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable_019e3c65-a2c0-77a9-b155-385b623c1ac7" xlink:to="loc_us-gaap_DebtInstrumentAxis_019e3c65-a2c0-7698-8fba-6030709d6616" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a2c0-7698-8fba-6030709d6616_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e3c65-a2c0-7698-8fba-6030709d6616" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a2c0-7698-8fba-6030709d6616_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a2c0-7909-997e-1bfbfe76426b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e3c65-a2c0-7698-8fba-6030709d6616" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a2c0-7909-997e-1bfbfe76426b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_SevenPointSevenFiveZeroSubordinatedNotesMember_019e3c65-a2c0-78fd-81ed-6d79fa23de4a" xlink:href="fihl-20260630.xsd#fihl_SevenPointSevenFiveZeroSubordinatedNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a2c0-7909-997e-1bfbfe76426b" xlink:to="loc_fihl_SevenPointSevenFiveZeroSubordinatedNotesMember_019e3c65-a2c0-78fd-81ed-6d79fa23de4a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_FourPointEightSevenFivePercentSeniorNotesMember_019e3c65-a2c0-7eef-8763-25f2e29707d1" xlink:href="fihl-20260630.xsd#fihl_FourPointEightSevenFivePercentSeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a2c0-7909-997e-1bfbfe76426b" xlink:to="loc_fihl_FourPointEightSevenFivePercentSeniorNotesMember_019e3c65-a2c0-7eef-8763-25f2e29707d1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_SixPointSixTwoFiveFixedRateResetJuniorSubordinatedNotesMember_019e3c65-a2c0-7fb6-87a6-7c1135713ae7" xlink:href="fihl-20260630.xsd#fihl_SixPointSixTwoFiveFixedRateResetJuniorSubordinatedNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a2c0-7909-997e-1bfbfe76426b" xlink:to="loc_fihl_SixPointSixTwoFiveFixedRateResetJuniorSubordinatedNotesMember_019e3c65-a2c0-7fb6-87a6-7c1135713ae7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_FixedRateResetSubordinatedNotesDue2055Member_019fd075-1cf4-737e-9e7f-7d69bf8ed8ff" xlink:href="fihl-20260630.xsd#fihl_FixedRateResetSubordinatedNotesDue2055Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a2c0-7909-997e-1bfbfe76426b" xlink:to="loc_fihl_FixedRateResetSubordinatedNotesDue2055Member_019fd075-1cf4-737e-9e7f-7d69bf8ed8ff" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_SeniorNotesDue2030Member_019fd075-1cf4-7423-bce5-51517876e969" xlink:href="fihl-20260630.xsd#fihl_SeniorNotesDue2030Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a2c0-7909-997e-1bfbfe76426b" xlink:to="loc_fihl_SeniorNotesDue2030Member_019fd075-1cf4-7423-bce5-51517876e969" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_FixedRateResetJuniorSubordinatedNotesDue2041Member_019fd075-1cf4-70b5-9f38-3bcfce5068e9" xlink:href="fihl-20260630.xsd#fihl_FixedRateResetJuniorSubordinatedNotesDue2041Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a2c0-7909-997e-1bfbfe76426b" xlink:to="loc_fihl_FixedRateResetJuniorSubordinatedNotesDue2041Member_019fd075-1cf4-70b5-9f38-3bcfce5068e9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e3c65-a2c0-7348-8d2d-c577e23a9dd4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable_019e3c65-a2c0-77a9-b155-385b623c1ac7" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e3c65-a2c0-7348-8d2d-c577e23a9dd4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a2c0-7348-8d2d-c577e23a9dd4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e3c65-a2c0-7348-8d2d-c577e23a9dd4" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a2c0-7348-8d2d-c577e23a9dd4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a2c0-7541-808c-dda4779a92b2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e3c65-a2c0-7348-8d2d-c577e23a9dd4" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a2c0-7541-808c-dda4779a92b2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubordinatedDebtMember_019e3c65-a2c0-7751-bed4-58d673c80385" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubordinatedDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a2c0-7541-808c-dda4779a92b2" xlink:to="loc_us-gaap_SubordinatedDebtMember_019e3c65-a2c0-7751-bed4-58d673c80385" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_019e3c65-a2c0-7f2b-ad95-b399b7a61899" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a2c0-7541-808c-dda4779a92b2" xlink:to="loc_us-gaap_SeniorNotesMember_019e3c65-a2c0-7f2b-ad95-b399b7a61899" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_JuniorSubordinatedDebtMember_019e3c65-a2c0-75c7-810a-64ac92fabae4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_JuniorSubordinatedDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a2c0-7541-808c-dda4779a92b2" xlink:to="loc_us-gaap_JuniorSubordinatedDebtMember_019e3c65-a2c0-75c7-810a-64ac92fabae4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e3c65-a2c0-787f-b628-ea068263128f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable_019e3c65-a2c0-77a9-b155-385b623c1ac7" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e3c65-a2c0-787f-b628-ea068263128f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e3c65-a2c0-787f-b628-ea068263128f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e3c65-a2c0-787f-b628-ea068263128f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e3c65-a2c0-787f-b628-ea068263128f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e3c65-a2c0-7b4e-8d42-9bfe8f9732d5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e3c65-a2c0-787f-b628-ea068263128f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e3c65-a2c0-7b4e-8d42-9bfe8f9732d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_019e3c65-a2c0-780a-b801-12773b6536b1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e3c65-a2c0-7b4e-8d42-9bfe8f9732d5" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_019e3c65-a2c0-780a-b801-12773b6536b1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e3c65-a2c0-7ea8-b4e2-eec62e4122fd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureAssetAndLiabilityNotMeasuredAtFairValueLineItems_019e3c65-a2c0-7010-acfd-469a889df88b" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e3c65-a2c0-7ea8-b4e2-eec62e4122fd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFairValue_019e3c65-a2c0-7a3e-ae38-701e0dc23c72" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureAssetAndLiabilityNotMeasuredAtFairValueLineItems_019e3c65-a2c0-7010-acfd-469a889df88b" xlink:to="loc_us-gaap_DebtInstrumentFairValue_019e3c65-a2c0-7a3e-ae38-701e0dc23c72" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/TotalCashCashEquivalentsRestrictedCashandRestrictedInvestmentsDetails" xlink:type="simple" xlink:href="fihl-20260630.xsd#TotalCashCashEquivalentsRestrictedCashandRestrictedInvestmentsDetails"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/TotalCashCashEquivalentsRestrictedCashandRestrictedInvestmentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsItemsLineItems_019e3c65-a2c0-7c1d-9e94-24a65acbf933" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsItemsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTable_019e3c65-a2c0-7155-9241-f1d04387cc0e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsItemsLineItems_019e3c65-a2c0-7c1d-9e94-24a65acbf933" xlink:to="loc_us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTable_019e3c65-a2c0-7155-9241-f1d04387cc0e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_019e3c65-a2c0-7ac5-8834-7324bf3c0201" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTable_019e3c65-a2c0-7155-9241-f1d04387cc0e" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_019e3c65-a2c0-7ac5-8834-7324bf3c0201" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e3c65-a2c0-7ac5-8834-7324bf3c0201_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_019e3c65-a2c0-7ac5-8834-7324bf3c0201" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e3c65-a2c0-7ac5-8834-7324bf3c0201_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e3c65-a2c0-73d0-a790-f043fc815d64" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_019e3c65-a2c0-7ac5-8834-7324bf3c0201" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e3c65-a2c0-73d0-a790-f043fc815d64" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialStandbyLetterOfCreditMember_019e3c65-a2c0-7c9d-b919-22145db4a60e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialStandbyLetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e3c65-a2c0-73d0-a790-f043fc815d64" xlink:to="loc_us-gaap_FinancialStandbyLetterOfCreditMember_019e3c65-a2c0-7c9d-b919-22145db4a60e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_ReinsuranceContractsMember_019e3c65-a2c0-7390-9380-a9d71a1779b2" xlink:href="fihl-20260630.xsd#fihl_ReinsuranceContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e3c65-a2c0-73d0-a790-f043fc815d64" xlink:to="loc_fihl_ReinsuranceContractsMember_019e3c65-a2c0-7390-9380-a9d71a1779b2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019e3c65-a2c0-7983-a5a4-42ef9b294cfe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsItemsLineItems_019e3c65-a2c0-7c1d-9e94-24a65acbf933" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019e3c65-a2c0-7983-a5a4-42ef9b294cfe" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalents_019e3c65-a2c0-7626-8770-a92d2771eb08" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsItemsLineItems_019e3c65-a2c0-7c1d-9e94-24a65acbf933" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalents_019e3c65-a2c0-7626-8770-a92d2771eb08" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019e3c65-a2c0-744e-b44c-76feee883590" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsItemsLineItems_019e3c65-a2c0-7c1d-9e94-24a65acbf933" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019e3c65-a2c0-744e-b44c-76feee883590" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedInvestments_019e3c65-a2c0-7d29-a1fc-ab246b07cfbd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsItemsLineItems_019e3c65-a2c0-7c1d-9e94-24a65acbf933" xlink:to="loc_us-gaap_RestrictedInvestments_019e3c65-a2c0-7d29-a1fc-ab246b07cfbd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_CashCashEquivalentsRestrictedCashRestrictedCashEquivalentsAndRestrictedInvestments_019e3c65-a2c0-7ad2-b1e3-6d5f8402176e" xlink:href="fihl-20260630.xsd#fihl_CashCashEquivalentsRestrictedCashRestrictedCashEquivalentsAndRestrictedInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsItemsLineItems_019e3c65-a2c0-7c1d-9e94-24a65acbf933" xlink:to="loc_fihl_CashCashEquivalentsRestrictedCashRestrictedCashEquivalentsAndRestrictedInvestments_019e3c65-a2c0-7ad2-b1e3-6d5f8402176e" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/DerivativeFinancialInstrumentsScheduleofFairValueandNotionalAmountsofDerivativeInstrumentsDetails" xlink:type="simple" xlink:href="fihl-20260630.xsd#DerivativeFinancialInstrumentsScheduleofFairValueandNotionalAmountsofDerivativeInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/DerivativeFinancialInstrumentsScheduleofFairValueandNotionalAmountsofDerivativeInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_019e3c65-a2c0-7592-ac01-101cb47ed9fd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_019e3c65-a2c0-7c9d-bae7-0c293bea4c1e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_019e3c65-a2c0-7592-ac01-101cb47ed9fd" xlink:to="loc_us-gaap_DerivativeTable_019e3c65-a2c0-7c9d-bae7-0c293bea4c1e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019e3c65-a2c0-731a-ad84-12bbf36ffe47" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_019e3c65-a2c0-7c9d-bae7-0c293bea4c1e" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019e3c65-a2c0-731a-ad84-12bbf36ffe47" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e3c65-a2c0-731a-ad84-12bbf36ffe47_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e3c65-a2c0-731a-ad84-12bbf36ffe47" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e3c65-a2c0-731a-ad84-12bbf36ffe47_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e3c65-a2c0-78a5-8ccc-1f4798622d07" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e3c65-a2c0-731a-ad84-12bbf36ffe47" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e3c65-a2c0-78a5-8ccc-1f4798622d07" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditDefaultSwapMember_019e3c65-a2c0-7ece-ac36-6bdb2606bf3a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditDefaultSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e3c65-a2c0-78a5-8ccc-1f4798622d07" xlink:to="loc_us-gaap_CreditDefaultSwapMember_019e3c65-a2c0-7ece-ac36-6bdb2606bf3a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForwardContractsMember_019e3c65-a2c0-7429-a646-34fcbd366bac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForwardContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e3c65-a2c0-78a5-8ccc-1f4798622d07" xlink:to="loc_us-gaap_ForwardContractsMember_019e3c65-a2c0-7429-a646-34fcbd366bac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_019e3c65-a2c0-76dd-8160-c3c1369315f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_019e3c65-a2c0-7c9d-bae7-0c293bea4c1e" xlink:to="loc_us-gaap_HedgingDesignationAxis_019e3c65-a2c0-76dd-8160-c3c1369315f2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019e3c65-a2c0-76dd-8160-c3c1369315f2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_019e3c65-a2c0-76dd-8160-c3c1369315f2" xlink:to="loc_us-gaap_HedgingDesignationDomain_019e3c65-a2c0-76dd-8160-c3c1369315f2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019e3c65-a2c0-787b-8b71-004916894d81" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_019e3c65-a2c0-76dd-8160-c3c1369315f2" xlink:to="loc_us-gaap_HedgingDesignationDomain_019e3c65-a2c0-787b-8b71-004916894d81" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_019e3c65-a2c0-75c1-9669-4143d6c64c92" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_019e3c65-a2c0-787b-8b71-004916894d81" xlink:to="loc_us-gaap_NondesignatedMember_019e3c65-a2c0-75c1-9669-4143d6c64c92" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeNetAbstract_019e3c65-a2c0-7890-9dbb-2c6d268d96c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeFairValueOfDerivativeNetAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019e3c65-a2c0-7592-ac01-101cb47ed9fd" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeNetAbstract_019e3c65-a2c0-7890-9dbb-2c6d268d96c1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_019e3c65-a2c0-7722-baff-a6624f7147dc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeFairValueOfDerivativeAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeFairValueOfDerivativeNetAbstract_019e3c65-a2c0-7890-9dbb-2c6d268d96c1" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_019e3c65-a2c0-7722-baff-a6624f7147dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_019e3c65-a2c0-7fe5-b752-94bf4704b358" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeFairValueOfDerivativeNetAbstract_019e3c65-a2c0-7890-9dbb-2c6d268d96c1" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_019e3c65-a2c0-7fe5-b752-94bf4704b358" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotionalAmountOfDerivativesAbstract_019e3c65-a2c0-7f22-8c2c-3bd51752232d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotionalAmountOfDerivativesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019e3c65-a2c0-7592-ac01-101cb47ed9fd" xlink:to="loc_us-gaap_NotionalAmountOfDerivativesAbstract_019e3c65-a2c0-7f22-8c2c-3bd51752232d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityNotionalAmount_019e3c65-a2c0-7136-9c3b-236e82db6b87" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLiabilityNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NotionalAmountOfDerivativesAbstract_019e3c65-a2c0-7f22-8c2c-3bd51752232d" xlink:to="loc_us-gaap_DerivativeLiabilityNotionalAmount_019e3c65-a2c0-7136-9c3b-236e82db6b87" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/DerivativeFinancialInstrumentsScheduleofNetChangeinNetUnrealizedGainsLossestoDerivativeInstrumentsDetails" xlink:type="simple" xlink:href="fihl-20260630.xsd#DerivativeFinancialInstrumentsScheduleofNetChangeinNetUnrealizedGainsLossestoDerivativeInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/DerivativeFinancialInstrumentsScheduleofNetChangeinNetUnrealizedGainsLossestoDerivativeInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_019e3c65-a2c0-7afe-aaa9-eaa907291536" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_019e3c65-a2c0-78ee-8468-593b1d4a5b81" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_019e3c65-a2c0-7afe-aaa9-eaa907291536" xlink:to="loc_us-gaap_DerivativeTable_019e3c65-a2c0-78ee-8468-593b1d4a5b81" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019e3c65-a2c0-7606-bc9b-b8c3909f5fa5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_019e3c65-a2c0-78ee-8468-593b1d4a5b81" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019e3c65-a2c0-7606-bc9b-b8c3909f5fa5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e3c65-a2c0-7606-bc9b-b8c3909f5fa5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e3c65-a2c0-7606-bc9b-b8c3909f5fa5" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e3c65-a2c0-7606-bc9b-b8c3909f5fa5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e3c65-a2c0-75b2-80f5-b41d79800938" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e3c65-a2c0-7606-bc9b-b8c3909f5fa5" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e3c65-a2c0-75b2-80f5-b41d79800938" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditDefaultSwapMember_019e3c65-a2c0-7f7e-9f4c-942dd7e1a0c6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditDefaultSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e3c65-a2c0-75b2-80f5-b41d79800938" xlink:to="loc_us-gaap_CreditDefaultSwapMember_019e3c65-a2c0-7f7e-9f4c-942dd7e1a0c6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForwardContractsMember_019e3c65-a2c0-7bbc-b545-c35ae8d2067b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForwardContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e3c65-a2c0-75b2-80f5-b41d79800938" xlink:to="loc_us-gaap_ForwardContractsMember_019e3c65-a2c0-7bbc-b545-c35ae8d2067b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeGainLossOnDerivativeNet_019e3c65-a2c0-7cdc-86f9-64b0ee361cb0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeGainLossOnDerivativeNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019e3c65-a2c0-7afe-aaa9-eaa907291536" xlink:to="loc_us-gaap_DerivativeGainLossOnDerivativeNet_019e3c65-a2c0-7cdc-86f9-64b0ee361cb0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrealizedGainLossOnDerivatives_019e3c65-a2c0-76fe-a448-41b4f8f8e6fe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UnrealizedGainLossOnDerivatives"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019e3c65-a2c0-7afe-aaa9-eaa907291536" xlink:to="loc_us-gaap_UnrealizedGainLossOnDerivatives_019e3c65-a2c0-76fe-a448-41b4f8f8e6fe" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/ReservesforLossesandLossAdjustmentExpensesNarrativeDetails" xlink:type="simple" xlink:href="fihl-20260630.xsd#ReservesforLossesandLossAdjustmentExpensesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/ReservesforLossesandLossAdjustmentExpensesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems_019e3c65-a2c0-7f49-9162-47775b5af676" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationTable_019e3c65-a2c0-7c1d-9fc5-efdc578de6ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems_019e3c65-a2c0-7f49-9162-47775b5af676" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationTable_019e3c65-a2c0-7c1d-9fc5-efdc578de6ed" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019e3c65-a2c0-7b48-86ff-b1578e01cdec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationTable_019e3c65-a2c0-7c1d-9fc5-efdc578de6ed" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019e3c65-a2c0-7b48-86ff-b1578e01cdec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e3c65-a2c0-7b48-86ff-b1578e01cdec_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e3c65-a2c0-7b48-86ff-b1578e01cdec" xlink:to="loc_us-gaap_SegmentDomain_019e3c65-a2c0-7b48-86ff-b1578e01cdec_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e3c65-a2c0-7e8d-882a-f69ec03ac08f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e3c65-a2c0-7b48-86ff-b1578e01cdec" xlink:to="loc_us-gaap_SegmentDomain_019e3c65-a2c0-7e8d-882a-f69ec03ac08f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_SpecialtyMember_019e3c65-a2c0-7569-949e-964bdbcd3219" xlink:href="fihl-20260630.xsd#fihl_SpecialtyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e3c65-a2c0-7e8d-882a-f69ec03ac08f" xlink:to="loc_fihl_SpecialtyMember_019e3c65-a2c0-7569-949e-964bdbcd3219" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_ReinsuranceMember_019e3c65-a2c0-78e9-b418-4d94417337f5" xlink:href="fihl-20260630.xsd#fihl_ReinsuranceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e3c65-a2c0-7e8d-882a-f69ec03ac08f" xlink:to="loc_fihl_ReinsuranceMember_019e3c65-a2c0-78e9-b418-4d94417337f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense_019e3c65-a2c0-7e9c-a0e2-955d673b39c8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems_019e3c65-a2c0-7f49-9162-47775b5af676" xlink:to="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense_019e3c65-a2c0-7e9c-a0e2-955d673b39c8" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/LongTermDebtNarrativeDetails" xlink:type="simple" xlink:href="fihl-20260630.xsd#LongTermDebtNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/LongTermDebtNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019e3c65-a371-77ff-98b1-d02d89ee928e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019e3c65-a371-7470-988f-700642951e9a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e3c65-a371-77ff-98b1-d02d89ee928e" xlink:to="loc_us-gaap_DebtInstrumentTable_019e3c65-a371-7470-988f-700642951e9a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019e3c65-a371-7bcf-9b72-c80202710cae" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e3c65-a371-7470-988f-700642951e9a" xlink:to="loc_us-gaap_DebtInstrumentAxis_019e3c65-a371-7bcf-9b72-c80202710cae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-7bcf-9b72-c80202710cae_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e3c65-a371-7bcf-9b72-c80202710cae" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-7bcf-9b72-c80202710cae_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-7335-8f2a-1d3679af3da6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e3c65-a371-7bcf-9b72-c80202710cae" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-7335-8f2a-1d3679af3da6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_FixedRateResetSubordinatedNotesDue2055Member_019e3c65-a371-76db-a053-86323b2a08bd" xlink:href="fihl-20260630.xsd#fihl_FixedRateResetSubordinatedNotesDue2055Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-7335-8f2a-1d3679af3da6" xlink:to="loc_fihl_FixedRateResetSubordinatedNotesDue2055Member_019e3c65-a371-76db-a053-86323b2a08bd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_FixedRateResetJuniorSubordinatedNotesDue2041Member_019e3c65-a371-793c-8be3-c71fdbafbf12" xlink:href="fihl-20260630.xsd#fihl_FixedRateResetJuniorSubordinatedNotesDue2041Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-7335-8f2a-1d3679af3da6" xlink:to="loc_fihl_FixedRateResetJuniorSubordinatedNotesDue2041Member_019e3c65-a371-793c-8be3-c71fdbafbf12" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_SeniorNotesDue2030Member_019e3c65-a371-7192-b57d-df683c3047a0" xlink:href="fihl-20260630.xsd#fihl_SeniorNotesDue2030Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-7335-8f2a-1d3679af3da6" xlink:to="loc_fihl_SeniorNotesDue2030Member_019e3c65-a371-7192-b57d-df683c3047a0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e3c65-a371-7a2e-bbac-a7611303d14f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e3c65-a371-7470-988f-700642951e9a" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e3c65-a371-7a2e-bbac-a7611303d14f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a371-7a2e-bbac-a7611303d14f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e3c65-a371-7a2e-bbac-a7611303d14f" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a371-7a2e-bbac-a7611303d14f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a371-785c-b4ed-39aa784001e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e3c65-a371-7a2e-bbac-a7611303d14f" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a371-785c-b4ed-39aa784001e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_JuniorSubordinatedDebtMember_019e3c65-a371-7cb0-9c08-6715dc570b58" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_JuniorSubordinatedDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a371-785c-b4ed-39aa784001e3" xlink:to="loc_us-gaap_JuniorSubordinatedDebtMember_019e3c65-a371-7cb0-9c08-6715dc570b58" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_019e3c65-a371-747e-923c-1b5aca7df4ff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a371-785c-b4ed-39aa784001e3" xlink:to="loc_us-gaap_SeniorNotesMember_019e3c65-a371-747e-923c-1b5aca7df4ff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_019e3c65-a371-717e-af30-1222129756c0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e3c65-a371-77ff-98b1-d02d89ee928e" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_019e3c65-a371-717e-af30-1222129756c0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e3c65-a371-71f7-a878-33cfc69ab557" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e3c65-a371-77ff-98b1-d02d89ee928e" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e3c65-a371-71f7-a878-33cfc69ab557" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeBasisSpreadOnVariableRate_019e3c65-a371-79eb-8bfb-514151c0fa70" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeBasisSpreadOnVariableRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e3c65-a371-77ff-98b1-d02d89ee928e" xlink:to="loc_us-gaap_DerivativeBasisSpreadOnVariableRate_019e3c65-a371-79eb-8bfb-514151c0fa70" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_019f6540-ef58-7a0a-9124-78c7e52b9f55" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e3c65-a371-77ff-98b1-d02d89ee928e" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_019f6540-ef58-7a0a-9124-78c7e52b9f55" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_019f6540-ef58-7817-a5e3-77ffa3cc97f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e3c65-a371-77ff-98b1-d02d89ee928e" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_019f6540-ef58-7817-a5e3-77ffa3cc97f3" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/LongTermDebtScheduleofDebtIssuedDetails" xlink:type="simple" xlink:href="fihl-20260630.xsd#LongTermDebtScheduleofDebtIssuedDetails"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/LongTermDebtScheduleofDebtIssuedDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019e3c65-a371-7e8e-8a1a-e3955f501760" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019e3c65-a371-73ea-ba2d-6c2e78e85394" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e3c65-a371-7e8e-8a1a-e3955f501760" xlink:to="loc_us-gaap_DebtInstrumentTable_019e3c65-a371-73ea-ba2d-6c2e78e85394" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019e3c65-a371-7423-9ec1-2bbdfcc7002c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e3c65-a371-73ea-ba2d-6c2e78e85394" xlink:to="loc_us-gaap_DebtInstrumentAxis_019e3c65-a371-7423-9ec1-2bbdfcc7002c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-7423-9ec1-2bbdfcc7002c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e3c65-a371-7423-9ec1-2bbdfcc7002c" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-7423-9ec1-2bbdfcc7002c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-7cc1-a2b8-8252ae49ab4c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e3c65-a371-7423-9ec1-2bbdfcc7002c" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-7cc1-a2b8-8252ae49ab4c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_FixedRateResetSubordinatedNotesDue2055Member_019e3c65-a371-7925-acf1-a253d7167d10" xlink:href="fihl-20260630.xsd#fihl_FixedRateResetSubordinatedNotesDue2055Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-7cc1-a2b8-8252ae49ab4c" xlink:to="loc_fihl_FixedRateResetSubordinatedNotesDue2055Member_019e3c65-a371-7925-acf1-a253d7167d10" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_SeniorNotesDue2030Member_019e3c65-a371-71b8-b026-9a1c505afe34" xlink:href="fihl-20260630.xsd#fihl_SeniorNotesDue2030Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-7cc1-a2b8-8252ae49ab4c" xlink:to="loc_fihl_SeniorNotesDue2030Member_019e3c65-a371-71b8-b026-9a1c505afe34" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_FixedRateResetJuniorSubordinatedNotesDue2041Member_019e3c65-a371-7323-af3b-209602d78f2b" xlink:href="fihl-20260630.xsd#fihl_FixedRateResetJuniorSubordinatedNotesDue2041Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-7cc1-a2b8-8252ae49ab4c" xlink:to="loc_fihl_FixedRateResetJuniorSubordinatedNotesDue2041Member_019e3c65-a371-7323-af3b-209602d78f2b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e3c65-a371-7765-bb6e-1278d4a8ba24" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e3c65-a371-73ea-ba2d-6c2e78e85394" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e3c65-a371-7765-bb6e-1278d4a8ba24" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a371-7765-bb6e-1278d4a8ba24_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e3c65-a371-7765-bb6e-1278d4a8ba24" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a371-7765-bb6e-1278d4a8ba24_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a371-7a0d-a754-6b4ac1dc24ab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e3c65-a371-7765-bb6e-1278d4a8ba24" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a371-7a0d-a754-6b4ac1dc24ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_019e3c65-a371-76b3-86c4-4c251a571d27" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a371-7a0d-a754-6b4ac1dc24ab" xlink:to="loc_us-gaap_SeniorNotesMember_019e3c65-a371-76b3-86c4-4c251a571d27" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_JuniorSubordinatedDebtMember_019e3c65-a371-701d-a00e-723101ad6daa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_JuniorSubordinatedDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a371-7a0d-a754-6b4ac1dc24ab" xlink:to="loc_us-gaap_JuniorSubordinatedDebtMember_019e3c65-a371-701d-a00e-723101ad6daa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubordinatedDebtMember_019fd075-ae8e-754c-b22f-ac3a6471f5bb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubordinatedDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a371-7a0d-a754-6b4ac1dc24ab" xlink:to="loc_us-gaap_SubordinatedDebtMember_019fd075-ae8e-754c-b22f-ac3a6471f5bb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_019e3c65-a371-7cc6-a535-b594da4da19e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e3c65-a371-7e8e-8a1a-e3955f501760" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_019e3c65-a371-7cc6-a535-b594da4da19e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscount_019e3c65-a371-73ad-8d37-f69fa9af8ab3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentUnamortizedDiscount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e3c65-a371-7e8e-8a1a-e3955f501760" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscount_019e3c65-a371-73ad-8d37-f69fa9af8ab3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e3c65-a371-7adc-92f1-4ed15c82816e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e3c65-a371-7e8e-8a1a-e3955f501760" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e3c65-a371-7adc-92f1-4ed15c82816e" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/CommitmentsandContingenciesDetails" xlink:type="simple" xlink:href="fihl-20260630.xsd#CommitmentsandContingenciesDetails"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/CommitmentsandContingenciesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_019e3c65-a371-7c2b-8c0a-015648d4e40a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_019e3c65-a371-722f-af48-bf3da7208a6b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e3c65-a371-7c2b-8c0a-015648d4e40a" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_019e3c65-a371-722f-af48-bf3da7208a6b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_TrancheAxis_019e3c65-a371-7ba3-ac84-d5e17b0909e1" xlink:href="fihl-20260630.xsd#fihl_TrancheAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e3c65-a371-722f-af48-bf3da7208a6b" xlink:to="loc_fihl_TrancheAxis_019e3c65-a371-7ba3-ac84-d5e17b0909e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_TrancheDomain_019e3c65-a371-7ba3-ac84-d5e17b0909e1_default" xlink:href="fihl-20260630.xsd#fihl_TrancheDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_fihl_TrancheAxis_019e3c65-a371-7ba3-ac84-d5e17b0909e1" xlink:to="loc_fihl_TrancheDomain_019e3c65-a371-7ba3-ac84-d5e17b0909e1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_TrancheDomain_019e3c65-a371-75a0-a396-e32eac46e397" xlink:href="fihl-20260630.xsd#fihl_TrancheDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_fihl_TrancheAxis_019e3c65-a371-7ba3-ac84-d5e17b0909e1" xlink:to="loc_fihl_TrancheDomain_019e3c65-a371-75a0-a396-e32eac46e397" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_UnsecuredTrancheMember_019e3c65-a371-77f9-a769-69d63033fa08" xlink:href="fihl-20260630.xsd#fihl_UnsecuredTrancheMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_fihl_TrancheDomain_019e3c65-a371-75a0-a396-e32eac46e397" xlink:to="loc_fihl_UnsecuredTrancheMember_019e3c65-a371-77f9-a769-69d63033fa08" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_SecuredTrancheMember_019e3c65-a371-7b7b-a765-98aea084c795" xlink:href="fihl-20260630.xsd#fihl_SecuredTrancheMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_fihl_TrancheDomain_019e3c65-a371-75a0-a396-e32eac46e397" xlink:to="loc_fihl_SecuredTrancheMember_019e3c65-a371-7b7b-a765-98aea084c795" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_UncommittedTrancheMember_019e3c65-a371-7a67-804e-6ab7d573075d" xlink:href="fihl-20260630.xsd#fihl_UncommittedTrancheMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_fihl_TrancheDomain_019e3c65-a371-75a0-a396-e32eac46e397" xlink:to="loc_fihl_UncommittedTrancheMember_019e3c65-a371-7a67-804e-6ab7d573075d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_SecuredAccordionMember_019e3c65-a371-7ff2-a658-215e667b79b6" xlink:href="fihl-20260630.xsd#fihl_SecuredAccordionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_fihl_TrancheDomain_019e3c65-a371-75a0-a396-e32eac46e397" xlink:to="loc_fihl_SecuredAccordionMember_019e3c65-a371-7ff2-a658-215e667b79b6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_019e3c65-a371-71d7-9b44-0c875af6ee57" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e3c65-a371-722f-af48-bf3da7208a6b" xlink:to="loc_us-gaap_CreditFacilityAxis_019e3c65-a371-71d7-9b44-0c875af6ee57" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019e3c65-a371-71d7-9b44-0c875af6ee57_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_019e3c65-a371-71d7-9b44-0c875af6ee57" xlink:to="loc_us-gaap_CreditFacilityDomain_019e3c65-a371-71d7-9b44-0c875af6ee57_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019e3c65-a371-76dc-b2ac-342b9564c0fd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_019e3c65-a371-71d7-9b44-0c875af6ee57" xlink:to="loc_us-gaap_CreditFacilityDomain_019e3c65-a371-76dc-b2ac-342b9564c0fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StandbyLettersOfCreditMember_019e3c65-a371-765f-8106-7714f7fbab2a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StandbyLettersOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019e3c65-a371-76dc-b2ac-342b9564c0fd" xlink:to="loc_us-gaap_StandbyLettersOfCreditMember_019e3c65-a371-765f-8106-7714f7fbab2a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019e3c65-a371-7b81-ad12-8575a246724d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e3c65-a371-722f-af48-bf3da7208a6b" xlink:to="loc_us-gaap_DebtInstrumentAxis_019e3c65-a371-7b81-ad12-8575a246724d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-7b81-ad12-8575a246724d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e3c65-a371-7b81-ad12-8575a246724d" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-7b81-ad12-8575a246724d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-75ca-b16d-728b7a57a7b8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e3c65-a371-7b81-ad12-8575a246724d" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-75ca-b16d-728b7a57a7b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_LloydsCreditAgreementMember_019e3c65-a371-7954-ac80-9bbee958c789" xlink:href="fihl-20260630.xsd#fihl_LloydsCreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-75ca-b16d-728b7a57a7b8" xlink:to="loc_fihl_LloydsCreditAgreementMember_019e3c65-a371-7954-ac80-9bbee958c789" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_CitibankCreditAgreementMember_019e3c65-a371-772e-ab54-fc5490b56875" xlink:href="fihl-20260630.xsd#fihl_CitibankCreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-75ca-b16d-728b7a57a7b8" xlink:to="loc_fihl_CitibankCreditAgreementMember_019e3c65-a371-772e-ab54-fc5490b56875" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_BarclaysCreditAgreementMember_019e3c65-a371-7aae-8147-3b6a4d498b9b" xlink:href="fihl-20260630.xsd#fihl_BarclaysCreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-75ca-b16d-728b7a57a7b8" xlink:to="loc_fihl_BarclaysCreditAgreementMember_019e3c65-a371-7aae-8147-3b6a4d498b9b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_BankOfMontrealCreditAgreementMember_019e3c65-a371-7c0e-a5ba-4dc2be0d6173" xlink:href="fihl-20260630.xsd#fihl_BankOfMontrealCreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e3c65-a371-75ca-b16d-728b7a57a7b8" xlink:to="loc_fihl_BankOfMontrealCreditAgreementMember_019e3c65-a371-7c0e-a5ba-4dc2be0d6173" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e3c65-a371-7eb4-bb92-7fa1a92d21ee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e3c65-a371-722f-af48-bf3da7208a6b" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e3c65-a371-7eb4-bb92-7fa1a92d21ee" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a371-7eb4-bb92-7fa1a92d21ee_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e3c65-a371-7eb4-bb92-7fa1a92d21ee" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a371-7eb4-bb92-7fa1a92d21ee_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a371-71c3-a8d2-3a3e591cd81c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e3c65-a371-7eb4-bb92-7fa1a92d21ee" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a371-71c3-a8d2-3a3e591cd81c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019e3c65-a371-700d-a22b-fceeea516773" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e3c65-a371-71c3-a8d2-3a3e591cd81c" xlink:to="loc_us-gaap_LineOfCreditMember_019e3c65-a371-700d-a22b-fceeea516773" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019e3c65-a371-7346-b5c7-ff47912294d2" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e3c65-a371-722f-af48-bf3da7208a6b" xlink:to="loc_srt_RangeAxis_019e3c65-a371-7346-b5c7-ff47912294d2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e3c65-a371-7346-b5c7-ff47912294d2_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019e3c65-a371-7346-b5c7-ff47912294d2" xlink:to="loc_srt_RangeMember_019e3c65-a371-7346-b5c7-ff47912294d2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e3c65-a371-7390-80a0-d4660a4bb2ee" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019e3c65-a371-7346-b5c7-ff47912294d2" xlink:to="loc_srt_RangeMember_019e3c65-a371-7390-80a0-d4660a4bb2ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019e3c65-a371-749a-af81-f02de9825c36" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e3c65-a371-7390-80a0-d4660a4bb2ee" xlink:to="loc_srt_MinimumMember_019e3c65-a371-749a-af81-f02de9825c36" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019e3c65-a371-7157-abf0-e1d21767aa97" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e3c65-a371-7390-80a0-d4660a4bb2ee" xlink:to="loc_srt_MaximumMember_019e3c65-a371-7157-abf0-e1d21767aa97" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_019e3c65-a371-7800-beac-21ad5bb74513" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e3c65-a371-7c2b-8c0a-015648d4e40a" xlink:to="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_019e3c65-a371-7800-beac-21ad5bb74513" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_019e3c65-a371-77e6-a766-648a67a9570d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e3c65-a371-7c2b-8c0a-015648d4e40a" xlink:to="loc_us-gaap_LineOfCredit_019e3c65-a371-77e6-a766-648a67a9570d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_019e3c65-a371-7aa5-a097-bc7efd80e787" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e3c65-a371-7c2b-8c0a-015648d4e40a" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_019e3c65-a371-7aa5-a097-bc7efd80e787" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_019e3c65-a371-7147-b7da-89267bba275a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e3c65-a371-7c2b-8c0a-015648d4e40a" xlink:to="loc_us-gaap_DebtInstrumentTerm_019e3c65-a371-7147-b7da-89267bba275a" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/RelatedPartyTransactionsNarrativeDetails" xlink:type="simple" xlink:href="fihl-20260630.xsd#RelatedPartyTransactionsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/RelatedPartyTransactionsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e3c65-a372-7395-b536-ca9a3e0fcf77" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e3c65-a372-7395-b536-ca9a3e0fcf77" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_019e3c65-a372-77f3-b7bd-4ebf06d09215" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e3c65-a372-7395-b536-ca9a3e0fcf77" xlink:to="loc_srt_OwnershipAxis_019e3c65-a372-77f3-b7bd-4ebf06d09215" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_019e3c65-a372-77f3-b7bd-4ebf06d09215_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_019e3c65-a372-77f3-b7bd-4ebf06d09215" xlink:to="loc_srt_OwnershipDomain_019e3c65-a372-77f3-b7bd-4ebf06d09215_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_019e3c65-a372-735d-93a9-8a07805764c0" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_019e3c65-a372-77f3-b7bd-4ebf06d09215" xlink:to="loc_srt_OwnershipDomain_019e3c65-a372-735d-93a9-8a07805764c0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_GroupMember_019e3c65-a372-7949-a417-7972cbda1a09" xlink:href="fihl-20260630.xsd#fihl_GroupMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_019e3c65-a372-735d-93a9-8a07805764c0" xlink:to="loc_fihl_GroupMember_019e3c65-a372-7949-a417-7972cbda1a09" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_019e3c65-a372-7285-ae9b-f62dc28421c2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e3c65-a372-7395-b536-ca9a3e0fcf77" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_019e3c65-a372-7285-ae9b-f62dc28421c2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_019e3c65-a372-7285-ae9b-f62dc28421c2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_019e3c65-a372-7285-ae9b-f62dc28421c2" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_019e3c65-a372-7285-ae9b-f62dc28421c2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_019e3c65-a372-7378-a145-cf9047969693" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_019e3c65-a372-7285-ae9b-f62dc28421c2" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_019e3c65-a372-7378-a145-cf9047969693" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_FrameworkAgreementMember_019e3c65-a372-7feb-8a53-41641b09c81c" xlink:href="fihl-20260630.xsd#fihl_FrameworkAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_019e3c65-a372-7378-a145-cf9047969693" xlink:to="loc_fihl_FrameworkAgreementMember_019e3c65-a372-7feb-8a53-41641b09c81c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a372-7e75-a806-17fd3c9ca680" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e3c65-a372-7395-b536-ca9a3e0fcf77" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a372-7e75-a806-17fd3c9ca680" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e3c65-a372-7e75-a806-17fd3c9ca680_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a372-7e75-a806-17fd3c9ca680" xlink:to="loc_us-gaap_RelatedPartyDomain_019e3c65-a372-7e75-a806-17fd3c9ca680_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e3c65-a372-7c98-93db-3489f1b0fd0d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a372-7e75-a806-17fd3c9ca680" xlink:to="loc_us-gaap_RelatedPartyDomain_019e3c65-a372-7c98-93db-3489f1b0fd0d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e3c65-a372-7164-8352-89c3cae9aed9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e3c65-a372-7c98-93db-3489f1b0fd0d" xlink:to="loc_us-gaap_RelatedPartyMember_019e3c65-a372-7164-8352-89c3cae9aed9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_019e3c65-a372-76f3-ae7b-d1070ab65c12" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e3c65-a372-7395-b536-ca9a3e0fcf77" xlink:to="loc_dei_LegalEntityAxis_019e3c65-a372-76f3-ae7b-d1070ab65c12" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019e3c65-a372-76f3-ae7b-d1070ab65c12_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_019e3c65-a372-76f3-ae7b-d1070ab65c12" xlink:to="loc_dei_EntityDomain_019e3c65-a372-76f3-ae7b-d1070ab65c12_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019e3c65-a372-7cc1-86c9-d7280271e56f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_019e3c65-a372-76f3-ae7b-d1070ab65c12" xlink:to="loc_dei_EntityDomain_019e3c65-a372-7cc1-86c9-d7280271e56f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_FidelisMGUMember_019e3c65-a372-7c31-9639-b43d72322277" xlink:href="fihl-20260630.xsd#fihl_FidelisMGUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_019e3c65-a372-7cc1-86c9-d7280271e56f" xlink:to="loc_fihl_FidelisMGUMember_019e3c65-a372-7c31-9639-b43d72322277" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_ThirdPartyManagingGeneralUnderwritersMember_019e3c65-a372-71f7-b0f6-b58f0dca44b7" xlink:href="fihl-20260630.xsd#fihl_ThirdPartyManagingGeneralUnderwritersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_019e3c65-a372-7cc1-86c9-d7280271e56f" xlink:to="loc_fihl_ThirdPartyManagingGeneralUnderwritersMember_019e3c65-a372-71f7-b0f6-b58f0dca44b7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019e3c65-a372-7b48-b097-03b9a661b202" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfIncomeLocationBalanceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e3c65-a372-7395-b536-ca9a3e0fcf77" xlink:to="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019e3c65-a372-7b48-b097-03b9a661b202" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_019e3c65-a372-7002-853f-70e86ecbeda3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_019e3c65-a372-7002-853f-70e86ecbeda3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_RelatedPartyTransactionAgreementDuration_019e3c65-a372-7948-9197-7f775626a73e" xlink:href="fihl-20260630.xsd#fihl_RelatedPartyTransactionAgreementDuration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_fihl_RelatedPartyTransactionAgreementDuration_019e3c65-a372-7948-9197-7f775626a73e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_ReinsuranceCededCommissionPercentage_019e3c65-a372-7d58-ad8e-7894fd8e82bb" xlink:href="fihl-20260630.xsd#fihl_ReinsuranceCededCommissionPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_fihl_ReinsuranceCededCommissionPercentage_019e3c65-a372-7d58-ad8e-7894fd8e82bb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyManagementFeePercentFee_019e3c65-a372-7b35-a2a4-3f992eab589e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyManagementFeePercentFee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_us-gaap_PropertyManagementFeePercentFee_019e3c65-a372-7b35-a2a4-3f992eab589e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_ReinsuranceProfitCommissionPercentage_019e3c65-a372-725b-8e73-06688ebf7fcb" xlink:href="fihl-20260630.xsd#fihl_ReinsuranceProfitCommissionPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_fihl_ReinsuranceProfitCommissionPercentage_019e3c65-a372-725b-8e73-06688ebf7fcb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_ReinsuranceProfitCommissionHurdleRateOfReturnPercentage_019e3c65-a372-7a86-a656-0d79be153bb6" xlink:href="fihl-20260630.xsd#fihl_ReinsuranceProfitCommissionHurdleRateOfReturnPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_fihl_ReinsuranceProfitCommissionHurdleRateOfReturnPercentage_019e3c65-a372-7a86-a656-0d79be153bb6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherReceivables_019e3c65-a372-7997-bf30-9217ce9fec35" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_us-gaap_OtherReceivables_019e3c65-a372-7997-bf30-9217ce9fec35" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrentAndNoncurrent_019e3c65-a372-7ba2-911a-003ae3ed8357" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_us-gaap_AccountsPayableCurrentAndNoncurrent_019e3c65-a372-7ba2-911a-003ae3ed8357" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionRate_019fc72f-24ea-701a-8926-7740246b570c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_us-gaap_RelatedPartyTransactionRate_019fc72f-24ea-701a-8926-7740246b570c" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InsuranceCommissions_019e3c65-a372-79b2-9ee7-52a5e9ad1a7d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InsuranceCommissions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_us-gaap_InsuranceCommissions_019e3c65-a372-79b2-9ee7-52a5e9ad1a7d" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForCommissions_019e3c65-a372-76e5-895e-10cdb3fa8189" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsForCommissions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_us-gaap_PaymentsForCommissions_019e3c65-a372-76e5-895e-10cdb3fa8189" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_RecoveryOfCommissions_019e3c65-a372-783a-84ab-4cf983b01def" xlink:href="fihl-20260630.xsd#fihl_RecoveryOfCommissions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_fihl_RecoveryOfCommissions_019e3c65-a372-783a-84ab-4cf983b01def" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpensesRelatedParty_019e3c65-a372-71f3-82a5-9e657d83074d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostsAndExpensesRelatedParty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_us-gaap_CostsAndExpensesRelatedParty_019e3c65-a372-71f3-82a5-9e657d83074d" xlink:type="arc" order="12"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/RelatedPartyTransactionsNarrativeDetails_1" xlink:type="simple" xlink:href="fihl-20260630.xsd#RelatedPartyTransactionsNarrativeDetails_1"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/RelatedPartyTransactionsNarrativeDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e3c65-a372-7395-b536-ca9a3e0fcf77" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e3c65-a372-7395-b536-ca9a3e0fcf77" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_019e3c65-a372-77f3-b7bd-4ebf06d09215" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e3c65-a372-7395-b536-ca9a3e0fcf77" xlink:to="loc_srt_OwnershipAxis_019e3c65-a372-77f3-b7bd-4ebf06d09215" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_019e3c65-a372-77f3-b7bd-4ebf06d09215_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_019e3c65-a372-77f3-b7bd-4ebf06d09215" xlink:to="loc_srt_OwnershipDomain_019e3c65-a372-77f3-b7bd-4ebf06d09215_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_019e3c65-a372-735d-93a9-8a07805764c0" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_019e3c65-a372-77f3-b7bd-4ebf06d09215" xlink:to="loc_srt_OwnershipDomain_019e3c65-a372-735d-93a9-8a07805764c0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_GroupMember_019e3c65-a372-7949-a417-7972cbda1a09" xlink:href="fihl-20260630.xsd#fihl_GroupMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_019e3c65-a372-735d-93a9-8a07805764c0" xlink:to="loc_fihl_GroupMember_019e3c65-a372-7949-a417-7972cbda1a09" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_019e3c65-a372-7285-ae9b-f62dc28421c2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e3c65-a372-7395-b536-ca9a3e0fcf77" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_019e3c65-a372-7285-ae9b-f62dc28421c2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_019e3c65-a372-7285-ae9b-f62dc28421c2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_019e3c65-a372-7285-ae9b-f62dc28421c2" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_019e3c65-a372-7285-ae9b-f62dc28421c2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_019e3c65-a372-7378-a145-cf9047969693" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_019e3c65-a372-7285-ae9b-f62dc28421c2" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_019e3c65-a372-7378-a145-cf9047969693" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_FrameworkAgreementMember_019e3c65-a372-7feb-8a53-41641b09c81c" xlink:href="fihl-20260630.xsd#fihl_FrameworkAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_019e3c65-a372-7378-a145-cf9047969693" xlink:to="loc_fihl_FrameworkAgreementMember_019e3c65-a372-7feb-8a53-41641b09c81c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a372-7e75-a806-17fd3c9ca680" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e3c65-a372-7395-b536-ca9a3e0fcf77" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a372-7e75-a806-17fd3c9ca680" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e3c65-a372-7e75-a806-17fd3c9ca680_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a372-7e75-a806-17fd3c9ca680" xlink:to="loc_us-gaap_RelatedPartyDomain_019e3c65-a372-7e75-a806-17fd3c9ca680_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e3c65-a372-7c98-93db-3489f1b0fd0d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a372-7e75-a806-17fd3c9ca680" xlink:to="loc_us-gaap_RelatedPartyDomain_019e3c65-a372-7c98-93db-3489f1b0fd0d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e3c65-a372-7164-8352-89c3cae9aed9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e3c65-a372-7c98-93db-3489f1b0fd0d" xlink:to="loc_us-gaap_RelatedPartyMember_019e3c65-a372-7164-8352-89c3cae9aed9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_019e3c65-a372-76f3-ae7b-d1070ab65c12" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e3c65-a372-7395-b536-ca9a3e0fcf77" xlink:to="loc_dei_LegalEntityAxis_019e3c65-a372-76f3-ae7b-d1070ab65c12" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019e3c65-a372-76f3-ae7b-d1070ab65c12_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_019e3c65-a372-76f3-ae7b-d1070ab65c12" xlink:to="loc_dei_EntityDomain_019e3c65-a372-76f3-ae7b-d1070ab65c12_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019e3c65-a372-7cc1-86c9-d7280271e56f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_019e3c65-a372-76f3-ae7b-d1070ab65c12" xlink:to="loc_dei_EntityDomain_019e3c65-a372-7cc1-86c9-d7280271e56f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_FidelisMGUMember_019e3c65-a372-7c31-9639-b43d72322277" xlink:href="fihl-20260630.xsd#fihl_FidelisMGUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_019e3c65-a372-7cc1-86c9-d7280271e56f" xlink:to="loc_fihl_FidelisMGUMember_019e3c65-a372-7c31-9639-b43d72322277" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_ThirdPartyManagingGeneralUnderwritersMember_019e3c65-a372-71f7-b0f6-b58f0dca44b7" xlink:href="fihl-20260630.xsd#fihl_ThirdPartyManagingGeneralUnderwritersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_019e3c65-a372-7cc1-86c9-d7280271e56f" xlink:to="loc_fihl_ThirdPartyManagingGeneralUnderwritersMember_019e3c65-a372-71f7-b0f6-b58f0dca44b7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_019e3c65-a372-7002-853f-70e86ecbeda3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_019e3c65-a372-7002-853f-70e86ecbeda3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_RelatedPartyTransactionAgreementDuration_019e3c65-a372-7948-9197-7f775626a73e" xlink:href="fihl-20260630.xsd#fihl_RelatedPartyTransactionAgreementDuration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_fihl_RelatedPartyTransactionAgreementDuration_019e3c65-a372-7948-9197-7f775626a73e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_ReinsuranceCededCommissionPercentage_019e3c65-a372-7d58-ad8e-7894fd8e82bb" xlink:href="fihl-20260630.xsd#fihl_ReinsuranceCededCommissionPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_fihl_ReinsuranceCededCommissionPercentage_019e3c65-a372-7d58-ad8e-7894fd8e82bb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyManagementFeePercentFee_019e3c65-a372-7b35-a2a4-3f992eab589e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyManagementFeePercentFee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_us-gaap_PropertyManagementFeePercentFee_019e3c65-a372-7b35-a2a4-3f992eab589e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_ReinsuranceProfitCommissionPercentage_019e3c65-a372-725b-8e73-06688ebf7fcb" xlink:href="fihl-20260630.xsd#fihl_ReinsuranceProfitCommissionPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_fihl_ReinsuranceProfitCommissionPercentage_019e3c65-a372-725b-8e73-06688ebf7fcb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_ReinsuranceProfitCommissionHurdleRateOfReturnPercentage_019e3c65-a372-7a86-a656-0d79be153bb6" xlink:href="fihl-20260630.xsd#fihl_ReinsuranceProfitCommissionHurdleRateOfReturnPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_fihl_ReinsuranceProfitCommissionHurdleRateOfReturnPercentage_019e3c65-a372-7a86-a656-0d79be153bb6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherReceivables_019e3c65-a372-7997-bf30-9217ce9fec35" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_us-gaap_OtherReceivables_019e3c65-a372-7997-bf30-9217ce9fec35" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrentAndNoncurrent_019e3c65-a372-7ba2-911a-003ae3ed8357" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_us-gaap_AccountsPayableCurrentAndNoncurrent_019e3c65-a372-7ba2-911a-003ae3ed8357" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionRate_019fc72f-24ea-701a-8926-7740246b570c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_us-gaap_RelatedPartyTransactionRate_019fc72f-24ea-701a-8926-7740246b570c" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InsuranceCommissions_019e3c65-a372-79b2-9ee7-52a5e9ad1a7d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InsuranceCommissions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_us-gaap_InsuranceCommissions_019e3c65-a372-79b2-9ee7-52a5e9ad1a7d" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForCommissions_019e3c65-a372-76e5-895e-10cdb3fa8189" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsForCommissions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_us-gaap_PaymentsForCommissions_019e3c65-a372-76e5-895e-10cdb3fa8189" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_RecoveryOfCommissions_019e3c65-a372-783a-84ab-4cf983b01def" xlink:href="fihl-20260630.xsd#fihl_RecoveryOfCommissions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_fihl_RecoveryOfCommissions_019e3c65-a372-783a-84ab-4cf983b01def" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpensesRelatedParty_019e3c65-a372-71f3-82a5-9e657d83074d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostsAndExpensesRelatedParty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7d87-a411-6cbd5a672437" xlink:to="loc_us-gaap_CostsAndExpensesRelatedParty_019e3c65-a372-71f3-82a5-9e657d83074d" xlink:type="arc" order="12"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/RelatedPartyTransactionsScheduleofCommissionsDetails" xlink:type="simple" xlink:href="fihl-20260630.xsd#RelatedPartyTransactionsScheduleofCommissionsDetails"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/RelatedPartyTransactionsScheduleofCommissionsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7374-9858-7989fdbed1e7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e3c65-a372-7a23-a542-a283201dee3e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7374-9858-7989fdbed1e7" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e3c65-a372-7a23-a542-a283201dee3e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a372-790a-9382-a0f1760061f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_019e3c65-a372-7a23-a542-a283201dee3e" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a372-790a-9382-a0f1760061f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e3c65-a372-790a-9382-a0f1760061f2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a372-790a-9382-a0f1760061f2" xlink:to="loc_us-gaap_RelatedPartyDomain_019e3c65-a372-790a-9382-a0f1760061f2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e3c65-a372-7897-b66d-e26956b55a23" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e3c65-a372-790a-9382-a0f1760061f2" xlink:to="loc_us-gaap_RelatedPartyDomain_019e3c65-a372-7897-b66d-e26956b55a23" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e3c65-a372-71d8-b677-7a61bed8f889" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e3c65-a372-7897-b66d-e26956b55a23" xlink:to="loc_us-gaap_RelatedPartyMember_019e3c65-a372-71d8-b677-7a61bed8f889" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_ReinsuranceCededCommissionExpense_019e3c65-a372-7765-8a1d-078d21bf991f" xlink:href="fihl-20260630.xsd#fihl_ReinsuranceCededCommissionExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7374-9858-7989fdbed1e7" xlink:to="loc_fihl_ReinsuranceCededCommissionExpense_019e3c65-a372-7765-8a1d-078d21bf991f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_ReinsuranceProfitCommissionExpense_019e3c65-a372-76bd-bd0e-636dd1b3fa16" xlink:href="fihl-20260630.xsd#fihl_ReinsuranceProfitCommissionExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7374-9858-7989fdbed1e7" xlink:to="loc_fihl_ReinsuranceProfitCommissionExpense_019e3c65-a372-76bd-bd0e-636dd1b3fa16" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_ReinsuranceCommissionExpense_019e3c65-a372-72f4-9fcd-96e6df9d9eed" xlink:href="fihl-20260630.xsd#fihl_ReinsuranceCommissionExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_019e3c65-a372-7374-9858-7989fdbed1e7" xlink:to="loc_fihl_ReinsuranceCommissionExpense_019e3c65-a372-72f4-9fcd-96e6df9d9eed" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.fidelisinsurance.com/role/ShareCapitalAuthorizedandIssuedNarrativeDetails" xlink:type="simple" xlink:href="fihl-20260630.xsd#ShareCapitalAuthorizedandIssuedNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.fidelisinsurance.com/role/ShareCapitalAuthorizedandIssuedNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalUnitLineItems_019e3c65-a372-7eff-8c21-5777d1f8fcf3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalUnitLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCapitalUnitsTable_019e3c65-a372-7275-a01a-85824d4e6e82" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfCapitalUnitsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CapitalUnitLineItems_019e3c65-a372-7eff-8c21-5777d1f8fcf3" xlink:to="loc_us-gaap_ScheduleOfCapitalUnitsTable_019e3c65-a372-7275-a01a-85824d4e6e82" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ShareRepurchaseProgramAxis_019e3c65-a372-7f6d-85cd-3539337824e7" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ShareRepurchaseProgramAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCapitalUnitsTable_019e3c65-a372-7275-a01a-85824d4e6e82" xlink:to="loc_srt_ShareRepurchaseProgramAxis_019e3c65-a372-7f6d-85cd-3539337824e7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ShareRepurchaseProgramDomain_019e3c65-a372-7f6d-85cd-3539337824e7_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ShareRepurchaseProgramDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ShareRepurchaseProgramAxis_019e3c65-a372-7f6d-85cd-3539337824e7" xlink:to="loc_srt_ShareRepurchaseProgramDomain_019e3c65-a372-7f6d-85cd-3539337824e7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ShareRepurchaseProgramDomain_019e3c65-a372-7e63-bf96-a1b7c74d3d24" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ShareRepurchaseProgramDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ShareRepurchaseProgramAxis_019e3c65-a372-7f6d-85cd-3539337824e7" xlink:to="loc_srt_ShareRepurchaseProgramDomain_019e3c65-a372-7e63-bf96-a1b7c74d3d24" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_ProgramMember_019e3c65-a372-76d6-9495-55f58f769802" xlink:href="fihl-20260630.xsd#fihl_ProgramMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ShareRepurchaseProgramDomain_019e3c65-a372-7e63-bf96-a1b7c74d3d24" xlink:to="loc_fihl_ProgramMember_019e3c65-a372-76d6-9495-55f58f769802" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_PineBrookFealIntermediateL.PMember_019f6545-5eba-7ed3-8a26-6763f42946f1" xlink:href="fihl-20260630.xsd#fihl_PineBrookFealIntermediateL.PMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ShareRepurchaseProgramDomain_019e3c65-a372-7e63-bf96-a1b7c74d3d24" xlink:to="loc_fihl_PineBrookFealIntermediateL.PMember_019f6545-5eba-7ed3-8a26-6763f42946f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_CVCFalconHoldingsLimitedMember_019e3c65-a372-79bf-889b-aec74d6a0b3f" xlink:href="fihl-20260630.xsd#fihl_CVCFalconHoldingsLimitedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ShareRepurchaseProgramDomain_019e3c65-a372-7e63-bf96-a1b7c74d3d24" xlink:to="loc_fihl_CVCFalconHoldingsLimitedMember_019e3c65-a372-79bf-889b-aec74d6a0b3f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_FidelisPartnershipMember_019e3c65-a372-792c-bb4e-e8fb75fc7351" xlink:href="fihl-20260630.xsd#fihl_FidelisPartnershipMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ShareRepurchaseProgramDomain_019e3c65-a372-7e63-bf96-a1b7c74d3d24" xlink:to="loc_fihl_FidelisPartnershipMember_019e3c65-a372-792c-bb4e-e8fb75fc7351" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockDividendsPerShareDeclared_019e3c65-a372-7f6a-9ff3-8f57edb369a9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockDividendsPerShareDeclared"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalUnitLineItems_019e3c65-a372-7eff-8c21-5777d1f8fcf3" xlink:to="loc_us-gaap_CommonStockDividendsPerShareDeclared_019e3c65-a372-7f6a-9ff3-8f57edb369a9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StockRepurchaseProgramAuthorizedAmount1_019e3c65-a372-7c2a-8086-eaf779393cbf" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StockRepurchaseProgramAuthorizedAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalUnitLineItems_019e3c65-a372-7eff-8c21-5777d1f8fcf3" xlink:to="loc_srt_StockRepurchaseProgramAuthorizedAmount1_019e3c65-a372-7c2a-8086-eaf779393cbf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockSharesAcquired_019e3c65-a372-76c9-8d61-e0ade99a3a48" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockSharesAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalUnitLineItems_019e3c65-a372-7eff-8c21-5777d1f8fcf3" xlink:to="loc_us-gaap_TreasuryStockSharesAcquired_019e3c65-a372-76c9-8d61-e0ade99a3a48" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_019e3c65-a372-770b-a2b0-b467646ea356" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalUnitLineItems_019e3c65-a372-7eff-8c21-5777d1f8fcf3" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_019e3c65-a372-770b-a2b0-b467646ea356" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_fihl_RepurchaseMechanismPercentage_019e3c65-a372-7a5c-93f2-46e6039f344e" xlink:href="fihl-20260630.xsd#fihl_RepurchaseMechanismPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalUnitLineItems_019e3c65-a372-7eff-8c21-5777d1f8fcf3" xlink:to="loc_fihl_RepurchaseMechanismPercentage_019e3c65-a372-7a5c-93f2-46e6039f344e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_019e3c65-a372-7c0e-9983-773bf18d2707" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalUnitLineItems_019e3c65-a372-7eff-8c21-5777d1f8fcf3" xlink:to="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_019e3c65-a372-7c0e-9983-773bf18d2707" xlink:type="arc" order="5"/>
  </link:definitionLink>
</link:linkbase>
