un·​faith·​ful | \ ˌən-ˈfāth-fəl How to pronounce unfaithful (audio) \

Definition of unfaithful

: not faithful:
a : not adhering to vows, allegiance, or duty : disloyal an unfaithful friend
b : not faithful to marriage vows suspected her husband of being unfaithful
c : inaccurate, untrustworthy an unfaithful copy of a document

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Other Words from unfaithful

unfaithfully \ ˌən-​ˈfāth-​fə-​lē How to pronounce unfaithful (audio) \ adverb
unfaithfulness noun

Examples of unfaithful in a Sentence

colonists who later proved to be unfaithful to the cause of independence
Recent Examples on the Web While Olindo has not yet revealed the cause of the split, her comments come after rumors that Shah was unfaithful in the relationship began circulating online. Dory Jackson, PEOPLE.com, 13 July 2021 Those diagnosed with it are unable to distinguish between reality and their delusions that a spouse or partner is being unfaithful. Annie Lane, oregonlive, 4 July 2021 Those diagnosed with it are unable to distinguish between reality and their delusions that a spouse or partner is being unfaithful. cleveland, 4 July 2021 In 2018, just days before Kardashian gave birth, when news broke that Thompson had been unfaithful during her pregnancy. Maria Pasquini, PEOPLE.com, 27 June 2021 Early in the trial, defense lawyers had tried to infer that Tibbetts' boyfriend, Dalton Jack, was unfaithful and struggled with anger issues. NBC News, 28 May 2021 Federico Fellini’s surrealistic account of a housewife who is told by a psychic that her husband has been unfaithful. Ed Stockly, Los Angeles Times, 9 Apr. 2021 Or rather its reappearance leads Flora to realize that Julian, her husband of 20 years, may have been unfaithful, and that her best friend Margot knows more than she's let on. Ew Staff, EW.com, 5 Apr. 2021 Then the bureau’s wiretaps and phone bugs revealed something else: King was unfaithful to his wife, Coretta Scott King. Chris Vognar, Los Angeles Times, 3 Mar. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'unfaithful.' 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 unfaithful

15th century, in the meaning defined above

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Time Traveler for unfaithful

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

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Statistics for unfaithful

Last Updated

17 Jul 2021

Cite this Entry

“Unfaithful.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/unfaithful. Accessed 24 Jul. 2021.

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More Definitions for unfaithful



English Language Learners Definition of unfaithful

: having a sexual relationship with someone who is not your wife, husband, or partner
: not accurate


un·​faith·​ful | \ ˌən-ˈfāth-fəl How to pronounce unfaithful (audio) \

Kids Definition of unfaithful

: not faithful : disloyal

More from Merriam-Webster on unfaithful

Nglish: Translation of unfaithful for Spanish Speakers

Britannica English: Translation of unfaithful for Arabic Speakers


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