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

Amidst rumors of a fling with Brody Jenner's ex Kaitlynn Carter, people were speculating that Miley's party habits and possible infidelity were the reason Liam filed for divorced. Jasmine Gomez, Seventeen, "Miley Cyrus Just Went on a Whole Twitter Rant About Her Pending Divorce From Liam Hemsworth," 22 Aug. 2019 Their dynamic — the love-hate relationship of two best friends trying to find their way back to each other after season one’s infidelity betrayal — has always been something of an anchor for the show. Pilot Viruet, Vox, "GLOW season 3 loses some of its trademark fun amid all the bloat," 13 Aug. 2019 As A Doll’s House had, Ghosts (1881)—with its revelations of infidelity, syphilis, and incestuous desire in a respectable bourgeois family—caused a scandal. Andrew Katzenstein, Harper's magazine, "The Radical Conservative," 16 Sep. 2019 There is substance abuse, infidelity, divorce, the whole lot. Abigail Van Buren, oregonlive, "Dear Abby: How to help a friend who’s struggled with depression for years, but isn’t interested in help," 13 Sep. 2019 There is substance abuse, infidelity, divorce, the whole lot. Abigail Van Buren, Twin Cities, "Dear Abby: Friend wants to be ready when man asks for help," 13 Sep. 2019 Wilson’s father, Clyde, had been hired by Ivana Trump to expose Donald Trump’s infidelity with Marla Maples—to arrange security at Post Oak. Kashmir Hill, The New Yorker, "The Perils of Semi-Legal Poker," 8 Sep. 2019 By 1976, Princess Margaret and the Earl of Snowdon had separated after years of infidelity on both sides. Caroline Hallemann, Town & Country, "Princess Margaret's Divorce Will Reportedly Feature in Season Three of The Crown," 14 Aug. 2019 The four mothers met years ago and have maintained a close bond through the usual challenges of infidelity, illness, divorce and widowhood. Ron Charles Critic, Washington Post, "Parents will stop at nothing to get their kids into a prestigious school," 16 July 2019

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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Last Updated

8 Oct 2019

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Time Traveler for infidelity

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

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