in·​fi·​del·​i·​ty | \ ˌin-fə-ˈde-lə-tē How to pronounce infidelity (audio) , -(ˌ)fī- \
plural infidelities

Definition of infidelity

1a : the act or fact of having a romantic or sexual relationship with someone other than one's husband, wife, or partner
b : unfaithfulness to a moral obligation : disloyalty
2 : lack of belief in a religion

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Examples of infidelity in a Sentence

She was convinced that her husband was guilty of infidelity. He has admitted to a number of marital infidelities.
Recent Examples on the Web The filing also revealed that the pair officially separated on April 20, just a day before PEOPLE learned that Kramer decided to file for divorce due to infidelity. Gabrielle Chung,, "Jana Kramer Says She Is Trying to Find a 'New Normal' After Filing for Divorce from Mike Caussin," 29 Apr. 2021 And indeed, according to a 2014 study by the American Psychological Association, 20% to 40% of divorces are caused by infidelity. Christopher Rosa, Glamour, "Willow Smith Opened Up About Being Polyamorous on Red Table Talk," 28 Apr. 2021 During their discussion, Leonard starts to confess to past sins: a wife and child abandoned, infidelity, lies. The New Yorker, "Briefly Noted," 15 Mar. 2021 There were also rumors of infidelity on Rodriguez's end. Christopher Rosa, Glamour, "Jennifer Lopez’s Reported Reason for Breaking Up With Alex Rodriguez Is So Sad," 21 Apr. 2021 Like any number of female Kennedys, like Coretta Scott King, like the Washington Post publisher Katharine Graham, and like others then (and since), Lady Bird suffered the humiliation of her husband’s flagrant infidelity. Liza Mundy, The Atlantic, "The Power of the First Lady," 20 Apr. 2021 In March it was widely reported that the pair had called off their engagement, with rumors of infidelity swirling. Caitlin O'kane, CBS News, "Jennifer Lopez and Alex Rodriguez announce breakup," 15 Apr. 2021 Or what to make of the drama's dainty hints of marital infidelity by Philip., "Prince Philip vs. Philip of ‘The Crown’: Fact and fiction," 12 Apr. 2021 The night turns into an alcohol-sodden marathon of recrimination, anger, self-laceration and infidelity. Washington Post, "George Segal, actor of roguish charm and wide dramatic range, dies at 87," 24 Mar. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'infidelity.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of infidelity

15th century, in the meaning defined at sense 2

History and Etymology for infidelity

Middle English infidelite, borrowed from Middle French infidelité, borrowed from Latin infidēlitāt-, infidēlitās "faithlessness, inconstancy," from infidēlis "unfaithful, disloyal" + -itāt-, -itās -ity — more at infidel entry 2

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Time Traveler for infidelity

Time Traveler

The first known use of infidelity was in the 15th century

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Statistics for infidelity

Last Updated

11 May 2021

Cite this Entry

“Infidelity.” Dictionary, Merriam-Webster, Accessed 13 May. 2021.

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