infidelity

noun

in·​fi·​del·​i·​ty ˌin-fə-ˈde-lə-tē How to pronounce infidelity (audio)
-(ˌ)fī-
plural infidelities
1
a
: 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

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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The entrepreneur and wellness coach addressed rumors of infidelity while responding directly to a fan’s accusation on Instagram. Amber Corrine, VIBE.com, 23 May 2025 Honey is typically in the business of infidelity, taking cases involving suspicious spouses and their philandering partners. Lovia Gyarkye, HollywoodReporter, 23 May 2025 But just as monogamy’s definition has changed and means different things to different people, the same is true for infidelity. Myisha Battle, Time, 19 May 2025 At 33, Brian, the Redditor's husband, firmly falls into this bracket, though the level of financial infidelity described in the social media post will take some beating. Jack Beresford, MSNBC Newsweek, 16 May 2025 See All Example Sentences for infidelity

Word History

Etymology

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

Browse Nearby Words

Cite this Entry

“Infidelity.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/infidelity. Accessed 3 Jun. 2025.

Kids Definition

infidelity

noun
in·​fi·​del·​i·​ty ˌin-fə-ˈdel-ət-ē How to pronounce infidelity (audio)
-(ˌ)fī-
plural infidelities
1
: lack of faith in a religion
2
: unfaithfulness especially to one's husband or wife

More from Merriam-Webster on infidelity

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!