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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019ce268-1342-778f-8e2e-5b2039cbee97,g:09f94e30-f03e-4df0-be30-63fb7f45738e-->
<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://xbrl.sec.gov/cef/role/SecurityOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/cef/2025/cef-2025.xsd#SecurityOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/cef/role/SecurityOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_A8.75SeriesATermPreferredSharesMember_019ce268-1342-767a-a0a2-041c394668b6" xlink:href="ck0001517767-20260331.xsd#ck0001517767_A8.75SeriesATermPreferredSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain" xlink:to="loc_ck0001517767_A8.75SeriesATermPreferredSharesMember_019ce268-1342-767a-a0a2-041c394668b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_A7.125SeriesBConvertiblePreferredSharesMember_019ce268-1342-7401-803b-b4b0f9b0c92f" xlink:href="ck0001517767-20260331.xsd#ck0001517767_A7.125SeriesBConvertiblePreferredSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain" xlink:to="loc_ck0001517767_A7.125SeriesBConvertiblePreferredSharesMember_019ce268-1342-7401-803b-b4b0f9b0c92f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_A7.50SeriesCConvertiblePreferredSharesMember_019ce268-1342-7f62-b0b1-58320c91d099" xlink:href="ck0001517767-20260331.xsd#ck0001517767_A7.50SeriesCConvertiblePreferredSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain" xlink:to="loc_ck0001517767_A7.50SeriesCConvertiblePreferredSharesMember_019ce268-1342-7f62-b0b1-58320c91d099" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/cef/role/RiskOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/cef/2025/cef-2025.xsd#RiskOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/cef/role/RiskOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_cef_AllRisksMember" xlink:href="https://xbrl.sec.gov/cef/2025/cef-2025.xsd#cef_AllRisksMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_PortfolioFairValueRiskMember_019ce268-1342-7a34-9851-9e3c9efbd6f7" xlink:href="ck0001517767-20260331.xsd#ck0001517767_PortfolioFairValueRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_PortfolioFairValueRiskMember_019ce268-1342-7a34-9851-9e3c9efbd6f7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_PotentialConflictsOfInterestRiskMember_019ce268-1342-7ab9-80b8-d00158e6eff0" xlink:href="ck0001517767-20260331.xsd#ck0001517767_PotentialConflictsOfInterestRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_PotentialConflictsOfInterestRiskMember_019ce268-1342-7ab9-80b8-d00158e6eff0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_CollateralizedLoanObligationsRiskMember_019ce268-1342-7061-97b4-f7056364d894" xlink:href="ck0001517767-20260331.xsd#ck0001517767_CollateralizedLoanObligationsRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_CollateralizedLoanObligationsRiskMember_019ce268-1342-7061-97b4-f7056364d894" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_CovenantLiteLoansRiskMember_019ce268-1342-74ac-b8d4-1be09c5c8377" xlink:href="ck0001517767-20260331.xsd#ck0001517767_CovenantLiteLoansRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_CovenantLiteLoansRiskMember_019ce268-1342-74ac-b8d4-1be09c5c8377" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_SubordinatedSecuritiesRiskMember_019ce268-1342-72ad-bed0-386f7a122c1f" xlink:href="ck0001517767-20260331.xsd#ck0001517767_SubordinatedSecuritiesRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_SubordinatedSecuritiesRiskMember_019ce268-1342-72ad-bed0-386f7a122c1f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_HighYieldInvestmentRiskMember_019ce268-1342-7dc3-8ec2-cc532130e4ec" xlink:href="ck0001517767-20260331.xsd#ck0001517767_HighYieldInvestmentRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_HighYieldInvestmentRiskMember_019ce268-1342-7dc3-8ec2-cc532130e4ec" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_DefaultRiskMember_019ce268-1342-72c4-9127-914c78a80662" xlink:href="ck0001517767-20260331.xsd#ck0001517767_DefaultRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_DefaultRiskMember_019ce268-1342-72c4-9127-914c78a80662" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_NonDiversificationRiskMember_019ce268-1342-705c-a62e-f1f7c18fec1f" xlink:href="ck0001517767-20260331.xsd#ck0001517767_NonDiversificationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_NonDiversificationRiskMember_019ce268-1342-705c-a62e-f1f7c18fec1f" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_LeverageRiskMember_019ce268-1342-7ce4-b5f7-10ad4a43ea09" xlink:href="ck0001517767-20260331.xsd#ck0001517767_LeverageRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_LeverageRiskMember_019ce268-1342-7ce4-b5f7-10ad4a43ea09" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_SeniorManagementPersonnelRiskMember_019ce268-1342-7965-bcf4-d2d85264a086" xlink:href="ck0001517767-20260331.xsd#ck0001517767_SeniorManagementPersonnelRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_SeniorManagementPersonnelRiskMember_019ce268-1342-7965-bcf4-d2d85264a086" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_ConflictsOfInterestRiskMember_019ce268-1342-7d57-ac1c-eb180095fbf1" xlink:href="ck0001517767-20260331.xsd#ck0001517767_ConflictsOfInterestRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_ConflictsOfInterestRiskMember_019ce268-1342-7d57-ac1c-eb180095fbf1" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_LiquidityRiskMember_019ce268-1342-730e-8bbf-1b8ac4d1ba1e" xlink:href="ck0001517767-20260331.xsd#ck0001517767_LiquidityRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_LiquidityRiskMember_019ce268-1342-730e-8bbf-1b8ac4d1ba1e" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_TheAdvisersIncentiveFeeRiskMember_019ce268-1342-7242-a533-bd813093a9c6" xlink:href="ck0001517767-20260331.xsd#ck0001517767_TheAdvisersIncentiveFeeRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_TheAdvisersIncentiveFeeRiskMember_019ce268-1342-7242-a533-bd813093a9c6" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_MarketRisksMember_019ce268-1342-7ce5-a3ad-4f9aad1ea071" xlink:href="ck0001517767-20260331.xsd#ck0001517767_MarketRisksMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_MarketRisksMember_019ce268-1342-7ce5-a3ad-4f9aad1ea071" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_InflationRiskMember_019ce268-1342-767a-bddd-2f1613d1dc3b" xlink:href="ck0001517767-20260331.xsd#ck0001517767_InflationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_InflationRiskMember_019ce268-1342-767a-bddd-2f1613d1dc3b" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_RegulatoryRiskMember_019ce268-1342-76da-85c9-ab6f19fae606" xlink:href="ck0001517767-20260331.xsd#ck0001517767_RegulatoryRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_RegulatoryRiskMember_019ce268-1342-76da-85c9-ab6f19fae606" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditRiskContractMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditRiskContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_us-gaap_CreditRiskContractMember" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_CreditSpreadRiskMember_019ce268-1342-78d5-81ad-50b2b076c627" xlink:href="ck0001517767-20260331.xsd#ck0001517767_CreditSpreadRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_CreditSpreadRiskMember_019ce268-1342-78d5-81ad-50b2b076c627" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaymentRiskMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PrepaymentRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_us-gaap_PrepaymentRiskMember" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_VolatilityRiskMember_019ce268-1342-76e8-a2e3-700e5a8d389c" xlink:href="ck0001517767-20260331.xsd#ck0001517767_VolatilityRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_VolatilityRiskMember_019ce268-1342-76e8-a2e3-700e5a8d389c" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_EquityRiskMember_019ce268-1342-7024-853d-001a3559c28f" xlink:href="ck0001517767-20260331.xsd#ck0001517767_EquityRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_EquityRiskMember_019ce268-1342-7024-853d-001a3559c28f" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_ForeignExchangeRateRiskMember_019ce268-1342-78e4-b289-55d21dc2a7bb" xlink:href="ck0001517767-20260331.xsd#ck0001517767_ForeignExchangeRateRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_ForeignExchangeRateRiskMember_019ce268-1342-78e4-b289-55d21dc2a7bb" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001517767_CybersecurityRiskMember_019ce268-1342-7dd7-8829-5e582ea6ded8" xlink:href="ck0001517767-20260331.xsd#ck0001517767_CybersecurityRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cef_AllRisksMember" xlink:to="loc_ck0001517767_CybersecurityRiskMember_019ce268-1342-7dd7-8829-5e582ea6ded8" xlink:type="arc" order="24"/>
  </link:definitionLink>
</link:linkbase>
