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 However, the couple's romance was later plagued by rumors of infidelity. Amy Mackelden, Harper's BAZAAR, "The Crown Doesn't Do Justice to Princess Anne's Real-Life Relationships," 4 Dec. 2019 There have been countless stories of genetic tests revealing that some children have different biological fathers, suggesting an infidelity that could lead to divorce. Katherine Ellen Foley, Quartz, "Why DNA testing kits shouldn’t be on your holiday shopping list," 21 Dec. 2019 At its most extreme, financial infidelity can lead to divorce and fiscal ruin., "The tales of deception you are about to read are true. The names of the perpetrators are being withheld to protect the guilty.," 15 Dec. 2019 Some lyrics deal with the death of his father, others with infidelity. Mark E. Perry, The Conversation, "‘The Wall’ cemented Pink Floyd’s fame – but destroyed the band," 27 Nov. 2019 Odom had previously been married to Khloe Kardashian from 2009-16 with the couple divorcing after Odom battled substance abuse issues and admitted to infidelities. Lorenzo Reyes, USA TODAY, "Ex-NBA star Lamar Odom announces his engagement to Sabrina Parr," 12 Nov. 2019 She’s in love with a fresh-faced young sailor (Burke Swanson), whom Serafina, having at last cottoned on to Rosario’s infidelity, treats like a seasoned predator. Alexandra Schwartz, The New Yorker, "American Dreams in “The Rose Tattoo” and “Soft Power”," 21 Oct. 2019 Porous electronic boundaries equate to more problematic relationships, with those most open to online infidelity the least happy and most likely to feel their current marriages or relationships will break up. Jay Nordlinger, National Review, "Marriage and Fidelity in the Internet Age," 6 Aug. 2019 My favorite book on infidelity contains insight into this relationship dynamic, as well as tools for healing. The Oregonian/oregonlive, al, "Ask Amy: Husband caught in 4 affairs blames hackers each time," 29 Apr. 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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Learn More about infidelity

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

15 Jan 2020

Cite this Entry

“Infidelity.” The Dictionary, Merriam-Webster Inc., Accessed 28 January 2020.

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Comments on infidelity

What made you want to look up infidelity? Please tell us where you read or heard it (including the quote, if possible).


showing steady, earnest care and effort

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