in·​fi·​del·​i·​ty ˌin-fə-ˈde-lə-tē How to pronounce infidelity (audio)
plural infidelities
: the act or fact of having a romantic or sexual relationship with someone other than one's husband, wife, or partner
: unfaithfulness to a moral obligation : disloyalty
: lack of belief in a religion

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 Lacking European sophistication, Allen still excuses infidelity as no big deal despite the fact that others hold it against you while indulging their own sins. Armond White, National Review, 5 Apr. 2024 For those unfamiliar with the very public infidelity and breakup Madix endured, she was cheated on (in her own home) by her boyfriend of a decade with her former good friend. Marianne Garvey, CNN, 29 Mar. 2024 Quiroga told officers that an argument between the two over infidelity and text messages erupted. Devoun Cetoute, Miami Herald, 7 Mar. 2024 Ethnographic studies indicate, for example, that the most common reasons unmarried women are no longer with the fathers of their children are the men’s violent behavior, infidelity and substance abuse. Eleanor Brown, The Conversation, 21 Feb. 2024 The next month, Nicki Nicole, the Argentinian singer Pluma had introduced as his girlfriend, shared a post alluding to their breakup over infidelity rumors, according to People. Angie Orellana Hernandez, Los Angeles Times, 15 Mar. 2024 Even dramatic tropes like infidelity feel organically incorporated. Alison Herman, Variety, 14 Mar. 2024 In the absence of other information, speculation has run rampant from serious surgery complications to divorce (over William’s rumored infidelity). Elizabeth Lopatto, The Verge, 13 Mar. 2024 After the child fell asleep, Colin-Gomez asked her to speak with him in the kitchen and allegedly accused her of infidelity, according to a police report cited by KRON 4. Samira Asma-Sadeque, Peoplemag, 26 Feb. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'infidelity.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


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

First Known Use

15th century, in the meaning defined at sense 2

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

Dictionary Entries Near infidelity

Cite this Entry

“Infidelity.” Dictionary, Merriam-Webster, Accessed 19 Apr. 2024.

Kids Definition


in·​fi·​del·​i·​ty ˌin-fə-ˈdel-ət-ē How to pronounce infidelity (audio)
plural infidelities
: lack of faith in a religion
: unfaithfulness especially to one's husband or wife

More from Merriam-Webster on infidelity

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