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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019e7471-8a94-79c9-abf1-0813d62ea292,g:965906e4-db23-4369-a70f-c899a12b79e0-->
<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.insperity.com/role/DocumentandEntityInformation" xlink:type="simple" xlink:href="nsp-20260630.xsd#DocumentandEntityInformation"/>
  <link:definitionLink xlink:role="http://www.insperity.com/role/DocumentandEntityInformation" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInformationLineItems_019e7471-8b6c-7b05-8a00-fe3887c78ec8" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitiesTable_019e7471-8b6c-7d3e-99e0-d3124e6e2f3e" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_019e7471-8b6c-7b05-8a00-fe3887c78ec8" xlink:to="loc_dei_EntitiesTable_019e7471-8b6c-7d3e-99e0-d3124e6e2f3e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityListingsExchangeAxis_019e7471-8b6c-79ad-8958-a8fe03bc44df" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityListingsExchangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_019e7471-8b6c-7d3e-99e0-d3124e6e2f3e" xlink:to="loc_dei_EntityListingsExchangeAxis_019e7471-8b6c-79ad-8958-a8fe03bc44df" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_ExchangeDomain_019e7471-8b6c-79ad-8958-a8fe03bc44df_default" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_ExchangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_EntityListingsExchangeAxis_019e7471-8b6c-79ad-8958-a8fe03bc44df" xlink:to="loc_dei_ExchangeDomain_019e7471-8b6c-79ad-8958-a8fe03bc44df_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_ExchangeDomain_019e7471-8b6c-794d-bb90-d9b2cae6f32e" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_ExchangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_EntityListingsExchangeAxis_019e7471-8b6c-79ad-8958-a8fe03bc44df" xlink:to="loc_dei_ExchangeDomain_019e7471-8b6c-794d-bb90-d9b2cae6f32e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019e7471-8b6c-773e-9548-b281385fdf58" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_ExchangeDomain_019e7471-8b6c-794d-bb90-d9b2cae6f32e" xlink:to="loc_us-gaap_CommonStockMember_019e7471-8b6c-773e-9548-b281385fdf58" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019e7471-8b6c-7429-8d5f-828a0b6ee532" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e7471-8b6c-7b05-8a00-fe3887c78ec8" xlink:to="loc_dei_Security12bTitle_019e7471-8b6c-7429-8d5f-828a0b6ee532" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019e7471-8b6c-7d95-98ee-a29c979211e3" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e7471-8b6c-7b05-8a00-fe3887c78ec8" xlink:to="loc_dei_TradingSymbol_019e7471-8b6c-7d95-98ee-a29c979211e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019e7471-8b6c-7cba-b0d1-147f44ede61a" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e7471-8b6c-7b05-8a00-fe3887c78ec8" xlink:to="loc_dei_SecurityExchangeName_019e7471-8b6c-7cba-b0d1-147f44ede61a" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.insperity.com/role/CONSOLIDATEDSTATEMENTOFSTOCKHOLDERSEQUITYUnaudited" xlink:type="simple" xlink:href="nsp-20260630.xsd#CONSOLIDATEDSTATEMENTOFSTOCKHOLDERSEQUITYUnaudited"/>
  <link:definitionLink xlink:role="http://www.insperity.com/role/CONSOLIDATEDSTATEMENTOFSTOCKHOLDERSEQUITYUnaudited" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e7471-8c34-7133-b6ff-477ecb841c67" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e7471-8c34-7520-8a65-ea2f98109006" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e7471-8c34-7133-b6ff-477ecb841c67" xlink:to="loc_us-gaap_StatementTable_019e7471-8c34-7520-8a65-ea2f98109006" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019e7471-8c34-7e81-8d46-49e2b6aa0872" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e7471-8c34-7520-8a65-ea2f98109006" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019e7471-8c34-7e81-8d46-49e2b6aa0872" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e7471-8c34-7e81-8d46-49e2b6aa0872_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e7471-8c34-7e81-8d46-49e2b6aa0872" xlink:to="loc_us-gaap_EquityComponentDomain_019e7471-8c34-7e81-8d46-49e2b6aa0872_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e7471-8c34-73da-b81b-2570d6bfa990" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e7471-8c34-7e81-8d46-49e2b6aa0872" xlink:to="loc_us-gaap_EquityComponentDomain_019e7471-8c34-73da-b81b-2570d6bfa990" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019e7471-8c34-765d-9e18-ebc819f46488" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e7471-8c34-73da-b81b-2570d6bfa990" xlink:to="loc_us-gaap_CommonStockMember_019e7471-8c34-765d-9e18-ebc819f46488" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_019e7471-8c34-7f55-975d-b5590b80f7de" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e7471-8c34-73da-b81b-2570d6bfa990" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_019e7471-8c34-7f55-975d-b5590b80f7de" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_019e7471-8c34-7f95-b57c-15b29079434e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockCommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e7471-8c34-73da-b81b-2570d6bfa990" xlink:to="loc_us-gaap_TreasuryStockCommonMember_019e7471-8c34-7f95-b57c-15b29079434e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_019e7471-8c34-7eff-84e7-90bc5020610c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e7471-8c34-73da-b81b-2570d6bfa990" xlink:to="loc_us-gaap_RetainedEarningsMember_019e7471-8c34-7eff-84e7-90bc5020610c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesIssued_019e7471-8c34-794c-b1da-1352a657b194" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e7471-8c34-7133-b6ff-477ecb841c67" xlink:to="loc_us-gaap_SharesIssued_019e7471-8c34-794c-b1da-1352a657b194" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e7471-8c34-7f73-b377-da5ceba818cd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e7471-8c34-7133-b6ff-477ecb841c67" xlink:to="loc_us-gaap_StockholdersEquity_019e7471-8c34-7f73-b377-da5ceba818cd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_019e7471-8c34-72db-bfea-3f63ff9157e5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e7471-8c34-7133-b6ff-477ecb841c67" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_019e7471-8c34-72db-bfea-3f63ff9157e5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_019e7471-8c34-7719-97fb-4eb9a8aedf0b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e7471-8c34-7133-b6ff-477ecb841c67" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_019e7471-8c34-7719-97fb-4eb9a8aedf0b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_019e7471-8c34-725d-bf5c-7cf1af45b1dd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e7471-8c34-7133-b6ff-477ecb841c67" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_019e7471-8c34-725d-bf5c-7cf1af45b1dd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityOther_019e7471-8c34-7548-a782-00b86706f8f6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e7471-8c34-7133-b6ff-477ecb841c67" xlink:to="loc_us-gaap_StockholdersEquityOther_019e7471-8c34-7548-a782-00b86706f8f6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStockCash_019e7471-8c34-79b8-89be-f01bd9f66f85" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DividendsCommonStockCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e7471-8c34-7133-b6ff-477ecb841c67" xlink:to="loc_us-gaap_DividendsCommonStockCash_019e7471-8c34-79b8-89be-f01bd9f66f85" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e7471-8c34-7b5d-8e38-d955dca51f6a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e7471-8c34-7133-b6ff-477ecb841c67" xlink:to="loc_us-gaap_NetIncomeLoss_019e7471-8c34-7b5d-8e38-d955dca51f6a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e7471-8c34-7e6a-ad05-dd5e3d524496" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesIssued_019e7471-8c34-7e9c-a9ef-a9acf697ec77" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharesIssued"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.insperity.com/role/AccountingPoliciesDetails" xlink:type="simple" xlink:href="nsp-20260630.xsd#AccountingPoliciesDetails"/>
  <link:definitionLink xlink:role="http://www.insperity.com/role/AccountingPoliciesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_019e7471-8c34-7ed0-a600-2c346dd98ce7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_019e7471-8c34-7a3b-8d34-239440b84085" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e7471-8c34-7ed0-a600-2c346dd98ce7" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_019e7471-8c34-7a3b-8d34-239440b84085" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_019e7471-8c34-7e35-a694-d6481113dcb5" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019e7471-8c34-7a3b-8d34-239440b84085" xlink:to="loc_srt_StatementGeographicalAxis_019e7471-8c34-7e35-a694-d6481113dcb5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019e7471-8c34-7e35-a694-d6481113dcb5_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_019e7471-8c34-7e35-a694-d6481113dcb5" xlink:to="loc_srt_SegmentGeographicalDomain_019e7471-8c34-7e35-a694-d6481113dcb5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019e7471-8c34-73dd-8324-f6aaeb377fb5" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_019e7471-8c34-7e35-a694-d6481113dcb5" xlink:to="loc_srt_SegmentGeographicalDomain_019e7471-8c34-73dd-8324-f6aaeb377fb5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_nsp_NortheastMember_019e7471-8c34-7cdc-9b45-cf47c9ccff25" xlink:href="nsp-20260630.xsd#nsp_NortheastMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019e7471-8c34-73dd-8324-f6aaeb377fb5" xlink:to="loc_nsp_NortheastMember_019e7471-8c34-7cdc-9b45-cf47c9ccff25" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_nsp_SoutheastMember_019e7471-8c34-79c2-b109-70366d054dc0" xlink:href="nsp-20260630.xsd#nsp_SoutheastMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019e7471-8c34-73dd-8324-f6aaeb377fb5" xlink:to="loc_nsp_SoutheastMember_019e7471-8c34-79c2-b109-70366d054dc0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_nsp_CentralMember_019e7471-8c34-739b-a8f6-b41d175434a9" xlink:href="nsp-20260630.xsd#nsp_CentralMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019e7471-8c34-73dd-8324-f6aaeb377fb5" xlink:to="loc_nsp_CentralMember_019e7471-8c34-739b-a8f6-b41d175434a9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_nsp_SouthwestMember_019e7471-8c34-7954-8d26-a24b1349e264" xlink:href="nsp-20260630.xsd#nsp_SouthwestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019e7471-8c34-73dd-8324-f6aaeb377fb5" xlink:to="loc_nsp_SouthwestMember_019e7471-8c34-7954-8d26-a24b1349e264" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_nsp_WestMember_019e7471-8c34-7185-a5ea-475430f30c79" xlink:href="nsp-20260630.xsd#nsp_WestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019e7471-8c34-73dd-8324-f6aaeb377fb5" xlink:to="loc_nsp_WestMember_019e7471-8c34-7185-a5ea-475430f30c79" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_nsp_OtherRevenuesMember_019e7471-8c34-7dd5-89eb-a416d6612121" xlink:href="nsp-20260630.xsd#nsp_OtherRevenuesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019e7471-8c34-73dd-8324-f6aaeb377fb5" xlink:to="loc_nsp_OtherRevenuesMember_019e7471-8c34-7dd5-89eb-a416d6612121" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e7471-8c34-789d-b93c-e497905eff5c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e7471-8c34-7ed0-a600-2c346dd98ce7" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e7471-8c34-789d-b93c-e497905eff5c" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.insperity.com/role/OtherBalanceSheetInformationDetails" xlink:type="simple" xlink:href="nsp-20260630.xsd#OtherBalanceSheetInformationDetails"/>
  <link:definitionLink xlink:role="http://www.insperity.com/role/OtherBalanceSheetInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsLineItems_019e7471-8c34-7819-9450-e54c0211623a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_019e7471-8c34-7d59-8720-ba565f10e909" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfCashAndCashEquivalentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e7471-8c34-7819-9450-e54c0211623a" xlink:to="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_019e7471-8c34-7d59-8720-ba565f10e909" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAxis_019e7471-8c34-7ce7-92f7-892e96269fa8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_019e7471-8c34-7d59-8720-ba565f10e909" xlink:to="loc_us-gaap_CashAndCashEquivalentsAxis_019e7471-8c34-7ce7-92f7-892e96269fa8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e7471-8c34-7ce7-92f7-892e96269fa8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_019e7471-8c34-7ce7-92f7-892e96269fa8" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e7471-8c34-7ce7-92f7-892e96269fa8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e7471-8c34-72ad-89b9-bcaac3ee9740" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_019e7471-8c34-7ce7-92f7-892e96269fa8" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e7471-8c34-72ad-89b9-bcaac3ee9740" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember_019e7471-8c34-7b51-9f27-e04dc31d47d5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MoneyMarketFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e7471-8c34-72ad-89b9-bcaac3ee9740" xlink:to="loc_us-gaap_MoneyMarketFundsMember_019e7471-8c34-7b51-9f27-e04dc31d47d5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsMember_019e7471-8c34-7e51-9c39-2a4aebf1ef54" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e7471-8c34-72ad-89b9-bcaac3ee9740" xlink:to="loc_us-gaap_CashAndCashEquivalentsMember_019e7471-8c34-7e51-9c39-2a4aebf1ef54" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_nsp_MoneyMarketFundsOvernightHoldingsAtCarryingValue_019e7471-8c34-705c-acd8-6841ccced6fa" xlink:href="nsp-20260630.xsd#nsp_MoneyMarketFundsOvernightHoldingsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e7471-8c34-7819-9450-e54c0211623a" xlink:to="loc_nsp_MoneyMarketFundsOvernightHoldingsAtCarryingValue_019e7471-8c34-705c-acd8-6841ccced6fa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestments_019e7471-8c34-7052-9a17-017b5270c066" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShortTermInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e7471-8c34-7819-9450-e54c0211623a" xlink:to="loc_us-gaap_ShortTermInvestments_019e7471-8c34-7052-9a17-017b5270c066" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Cash_019e7471-8c34-7fb1-aafb-a64a54ecfe1a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Cash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e7471-8c34-7819-9450-e54c0211623a" xlink:to="loc_us-gaap_Cash_019e7471-8c34-7fb1-aafb-a64a54ecfe1a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_DraftsPayable_019e7471-8c34-7d42-b577-46fe77c6ff41" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_DraftsPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e7471-8c34-7819-9450-e54c0211623a" xlink:to="loc_srt_DraftsPayable_019e7471-8c34-7d42-b577-46fe77c6ff41" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsAndShortTermInvestments_019e7471-8c34-7c4a-99b1-7681c2eeb962" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashCashEquivalentsAndShortTermInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e7471-8c34-7819-9450-e54c0211623a" xlink:to="loc_us-gaap_CashCashEquivalentsAndShortTermInvestments_019e7471-8c34-7c4a-99b1-7681c2eeb962" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_nsp_PayrollWithholdingsIncludedInCashBalance_019e7471-8c34-7142-9d8d-0361d474604f" xlink:href="nsp-20260630.xsd#nsp_PayrollWithholdingsIncludedInCashBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e7471-8c34-7819-9450-e54c0211623a" xlink:to="loc_nsp_PayrollWithholdingsIncludedInCashBalance_019e7471-8c34-7142-9d8d-0361d474604f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_nsp_ClientPrepaymentsIncludedInCashBalance_019e7471-8c34-70cd-99a3-5a5fae1cdd53" xlink:href="nsp-20260630.xsd#nsp_ClientPrepaymentsIncludedInCashBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e7471-8c34-7819-9450-e54c0211623a" xlink:to="loc_nsp_ClientPrepaymentsIncludedInCashBalance_019e7471-8c34-70cd-99a3-5a5fae1cdd53" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019e7471-8c34-74dd-858a-9d1cf5a55427" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e7471-8c34-7819-9450-e54c0211623a" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019e7471-8c34-74dd-858a-9d1cf5a55427" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_019e7471-8c34-7e56-8cfc-62452994de63" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e7471-8c34-7819-9450-e54c0211623a" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_019e7471-8c34-7e56-8cfc-62452994de63" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FundsHeldForClients_019e7471-8c34-751b-9259-25d9212590f2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FundsHeldForClients"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e7471-8c34-7819-9450-e54c0211623a" xlink:to="loc_us-gaap_FundsHeldForClients_019e7471-8c34-751b-9259-25d9212590f2" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_nsp_DepositsWorkersCompensation_019e7471-8c34-7727-8d5b-1c244c90aa6f" xlink:href="nsp-20260630.xsd#nsp_DepositsWorkersCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e7471-8c34-7819-9450-e54c0211623a" xlink:to="loc_nsp_DepositsWorkersCompensation_019e7471-8c34-7727-8d5b-1c244c90aa6f" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019e7471-8c34-7be6-97f6-c05054710e6e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e7471-8c34-7819-9450-e54c0211623a" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019e7471-8c34-7be6-97f6-c05054710e6e" xlink:type="arc" order="11"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.insperity.com/role/FairValueMeasurementsFairValueMeasurementsDetails" xlink:type="simple" xlink:href="nsp-20260630.xsd#FairValueMeasurementsFairValueMeasurementsDetails"/>
  <link:definitionLink xlink:role="http://www.insperity.com/role/FairValueMeasurementsFairValueMeasurementsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e7471-8c34-7514-baf6-9cd10f5400f0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019e7471-8c34-7449-b5bb-853810e91f0c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e7471-8c34-7514-baf6-9cd10f5400f0" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019e7471-8c34-7449-b5bb-853810e91f0c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e7471-8c34-7120-9640-a0306e8e8011" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019e7471-8c34-7449-b5bb-853810e91f0c" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e7471-8c34-7120-9640-a0306e8e8011" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e7471-8c34-7120-9640-a0306e8e8011_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e7471-8c34-7120-9640-a0306e8e8011" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e7471-8c34-7120-9640-a0306e8e8011_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e7471-8c34-72de-bfa6-d23ac9d7de13" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e7471-8c34-7120-9640-a0306e8e8011" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e7471-8c34-72de-bfa6-d23ac9d7de13" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel12And3Member_019e7471-8c34-7432-a9ac-28543545bf97" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel12And3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e7471-8c34-72de-bfa6-d23ac9d7de13" xlink:to="loc_us-gaap_FairValueInputsLevel12And3Member_019e7471-8c34-7432-a9ac-28543545bf97" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_019e7471-8c34-789e-b639-d9a3288b27c8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueInputsLevel12And3Member_019e7471-8c34-7432-a9ac-28543545bf97" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_019e7471-8c34-789e-b639-d9a3288b27c8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e7471-8c34-790a-80d0-abb4fc847b5f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019e7471-8c34-7449-b5bb-853810e91f0c" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e7471-8c34-790a-80d0-abb4fc847b5f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e7471-8c34-790a-80d0-abb4fc847b5f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e7471-8c34-790a-80d0-abb4fc847b5f" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e7471-8c34-790a-80d0-abb4fc847b5f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e7471-8c34-73a6-99eb-74c9c6de0a59" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e7471-8c34-790a-80d0-abb4fc847b5f" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e7471-8c34-73a6-99eb-74c9c6de0a59" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_019e7471-8c34-7ad7-a160-0e84e2ee3122" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e7471-8c34-73a6-99eb-74c9c6de0a59" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_019e7471-8c34-7ad7-a160-0e84e2ee3122" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_019e7471-8c34-7fa4-be15-56c0b20ee862" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e7471-8c34-7514-baf6-9cd10f5400f0" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_019e7471-8c34-7fa4-be15-56c0b20ee862" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentSecuritiesAtCarryingValue_019e7471-8c34-7dd7-a5f1-78596b9ead64" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_USGovernmentSecuritiesAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e7471-8c34-7514-baf6-9cd10f5400f0" xlink:to="loc_us-gaap_USGovernmentSecuritiesAtCarryingValue_019e7471-8c34-7dd7-a5f1-78596b9ead64" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCashEquivalentsAtCarryingValue_019e7471-8c34-7cf1-88dd-a7ad2b997531" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e7471-8c34-7514-baf6-9cd10f5400f0" xlink:to="loc_us-gaap_OtherCashEquivalentsAtCarryingValue_019e7471-8c34-7cf1-88dd-a7ad2b997531" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_019e7471-8c34-70bf-b059-58870cf35cb4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e7471-8c34-7514-baf6-9cd10f5400f0" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_019e7471-8c34-70bf-b059-58870cf35cb4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_019e7471-8c34-7cc3-9989-b85922f42f71" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e7471-8c34-7514-baf6-9cd10f5400f0" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_019e7471-8c34-7cc3-9989-b85922f42f71" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_019e7471-8c34-7d30-a660-9f0da173ee1e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e7471-8c34-7514-baf6-9cd10f5400f0" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_019e7471-8c34-7d30-a660-9f0da173ee1e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_019e7471-8c34-758f-bcfe-a42ca7bc06c1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e7471-8c34-7514-baf6-9cd10f5400f0" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_019e7471-8c34-758f-bcfe-a42ca7bc06c1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_019e7471-8c34-723d-840d-fd63f89a4162" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e7471-8c34-7514-baf6-9cd10f5400f0" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_019e7471-8c34-723d-840d-fd63f89a4162" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.insperity.com/role/LongtermDebtDetails" xlink:type="simple" xlink:href="nsp-20260630.xsd#LongtermDebtDetails"/>
  <link:definitionLink xlink:role="http://www.insperity.com/role/LongtermDebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_019e7471-8c34-791e-83e0-d7569a2fe873" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_019e7471-8c34-7d21-b644-d6e03a632b62" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e7471-8c34-791e-83e0-d7569a2fe873" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_019e7471-8c34-7d21-b644-d6e03a632b62" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_019e7471-8c34-7329-9ad8-93166ec0bc65" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e7471-8c34-7d21-b644-d6e03a632b62" xlink:to="loc_us-gaap_CreditFacilityAxis_019e7471-8c34-7329-9ad8-93166ec0bc65" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019e7471-8c34-7329-9ad8-93166ec0bc65_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_019e7471-8c34-7329-9ad8-93166ec0bc65" xlink:to="loc_us-gaap_CreditFacilityDomain_019e7471-8c34-7329-9ad8-93166ec0bc65_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019e7471-8c34-7b5f-bf6a-6a4f52eb93d9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_019e7471-8c34-7329-9ad8-93166ec0bc65" xlink:to="loc_us-gaap_CreditFacilityDomain_019e7471-8c34-7b5f-bf6a-6a4f52eb93d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BaseRateMember_019e7471-8c34-7ae9-8f7d-c0c8043cadad" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BaseRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019e7471-8c34-7b5f-bf6a-6a4f52eb93d9" xlink:to="loc_us-gaap_BaseRateMember_019e7471-8c34-7ae9-8f7d-c0c8043cadad" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_019e7471-8c34-7739-b0c0-8d1f501a5ccb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019e7471-8c34-7b5f-bf6a-6a4f52eb93d9" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_019e7471-8c34-7739-b0c0-8d1f501a5ccb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019e7471-8c34-73c7-b14a-55cd416e4874" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e7471-8c34-7d21-b644-d6e03a632b62" xlink:to="loc_srt_RangeAxis_019e7471-8c34-73c7-b14a-55cd416e4874" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e7471-8c34-73c7-b14a-55cd416e4874_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019e7471-8c34-73c7-b14a-55cd416e4874" xlink:to="loc_srt_RangeMember_019e7471-8c34-73c7-b14a-55cd416e4874_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e7471-8c34-764c-bed5-caeed02ca54c" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019e7471-8c34-73c7-b14a-55cd416e4874" xlink:to="loc_srt_RangeMember_019e7471-8c34-764c-bed5-caeed02ca54c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019e7471-8c34-75d9-8316-d665291c5e77" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e7471-8c34-764c-bed5-caeed02ca54c" xlink:to="loc_srt_MinimumMember_019e7471-8c34-75d9-8316-d665291c5e77" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019e7471-8c34-78d7-80e7-c685027f26c2" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e7471-8c34-764c-bed5-caeed02ca54c" xlink:to="loc_srt_MaximumMember_019e7471-8c34-78d7-80e7-c685027f26c2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_019e7471-8c34-70c3-ab19-37ab7298aea5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e7471-8c34-791e-83e0-d7569a2fe873" xlink:to="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_019e7471-8c34-70c3-ab19-37ab7298aea5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019e7471-8c34-7c9e-ae96-87ee4ef27a49" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e7471-8c34-791e-83e0-d7569a2fe873" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019e7471-8c34-7c9e-ae96-87ee4ef27a49" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_nsp_PercentageOfSubsidiaryStockSecuringDebt_019e7471-8c34-7245-b9d5-3ec2c6e00df8" xlink:href="nsp-20260630.xsd#nsp_PercentageOfSubsidiaryStockSecuringDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e7471-8c34-791e-83e0-d7569a2fe873" xlink:to="loc_nsp_PercentageOfSubsidiaryStockSecuringDebt_019e7471-8c34-7245-b9d5-3ec2c6e00df8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_019e7471-8c34-780b-943a-9fd8f57d4417" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e7471-8c34-791e-83e0-d7569a2fe873" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_019e7471-8c34-780b-943a-9fd8f57d4417" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_019e7471-8c34-74b3-ab2a-e2f245b6c114" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e7471-8c34-791e-83e0-d7569a2fe873" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_019e7471-8c34-74b3-ab2a-e2f245b6c114" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_019e7471-8c34-7956-8caa-486d2f1224d7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e7471-8c34-791e-83e0-d7569a2fe873" xlink:to="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_019e7471-8c34-7956-8caa-486d2f1224d7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturityDate_019e7471-8c34-75c3-a3c6-74cc7fc8602c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtMaturityDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e7471-8c34-791e-83e0-d7569a2fe873" xlink:to="loc_us-gaap_LongTermDebtMaturityDate_019e7471-8c34-75c3-a3c6-74cc7fc8602c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019e7471-8c34-77e8-bcec-3cea4ae4478e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e7471-8c34-791e-83e0-d7569a2fe873" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019e7471-8c34-77e8-bcec-3cea4ae4478e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_nsp_ApplicableMarginFederalFundsRate_019e7471-8c34-778f-9973-363f7dbb9722" xlink:href="nsp-20260630.xsd#nsp_ApplicableMarginFederalFundsRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e7471-8c34-791e-83e0-d7569a2fe873" xlink:to="loc_nsp_ApplicableMarginFederalFundsRate_019e7471-8c34-778f-9973-363f7dbb9722" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_nsp_AdjustedTermSOFRRatePlusApplicableMargin_019e7471-8c34-78e3-b097-cd355df7fcc4" xlink:href="nsp-20260630.xsd#nsp_AdjustedTermSOFRRatePlusApplicableMargin"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e7471-8c34-791e-83e0-d7569a2fe873" xlink:to="loc_nsp_AdjustedTermSOFRRatePlusApplicableMargin_019e7471-8c34-78e3-b097-cd355df7fcc4" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_019e7471-8c34-7e77-9f3c-8bab034b418e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e7471-8c34-791e-83e0-d7569a2fe873" xlink:to="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_019e7471-8c34-7e77-9f3c-8bab034b418e" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityInterestRateDuringPeriod_019e7471-8c34-7b2e-a9df-158ea64a4f92" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityInterestRateDuringPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e7471-8c34-791e-83e0-d7569a2fe873" xlink:to="loc_us-gaap_LineOfCreditFacilityInterestRateDuringPeriod_019e7471-8c34-7b2e-a9df-158ea64a4f92" xlink:type="arc" order="11"/>
  </link:definitionLink>
</link:linkbase>
