un·​faith·​ful | \ˌən-ˈfāth-fəl \

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 \ 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

Pascal Greggory and John Malkovich also have juicy roles, as Gilberte’s unfaithful husband and the cheerfully depraved Baron de Charlus. J. Hoberman, New York Times, "Revived and Still Luxurious: Raúl Ruiz’s Search for Proust," 8 Feb. 2018 The couple’s relationship has been rocky after it was revealed that Josh was unfaithful to his wife and used adultery site Ashley Madison to cheat. Kathleen Joyce, Fox News, "Anna Duggar says 'past 10 years' with husband Josh Duggar 'have been a wonderful adventure'," 6 July 2018 Her husband, who was said to have been unfaithful, was convicted, but there are doubts, according to a news release from the TV channel. Joshua Sharpe, ajc, "TV show: DeKalb man might be innocent in wife’s murder," 12 July 2018 Her subjects ranged from the Habsburg Empire’s high nobility, shown at play in late World War I-era issues of society magazines, to Vienna’s high-culture heartbreaker, Alma Mahler, Gustav’s unfaithful wife. J.s. Marcus, WSJ, "Faces of Old Vienna," 12 July 2018 Libbie Custer is a compelling character, a fierce woman devoted to an unfaithful but passionate husband, who loves battle above all else. Sophie Haigney, SFChronicle.com, "‘The Removes,’ by Tatjana Soli," 21 June 2018 Earlier this month, author Michael Wolff of the bestselling Fire and Fury: Inside the Trump White House, hinted to Bill Maher that Trump remains unfaithful to his wife, and is currently having an affair inside the White House. Karen Mizoguchi, PEOPLE.com, "'Furious' Melania Trump's Escape to Mar-a-Lago Spa Cost Taxpayers $64,000: Report," 30 Jan. 2018 Apparently, Richie has decided to end the relationship, following allegations that Disick had been unfaithful. Amy Mackelden, Harper's BAZAAR, "Sofia Richie Splits from Scott Disick Following Cheating Claims," 3 June 2018 Apparently, the incident at the listening party wasn’t the first time Disick was unfaithful. Amanda Arnold, The Cut, "Sofia Richie Reportedly Dumped Scott Disick After He Cheated On Her," 3 June 2018

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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Last Updated

29 Oct 2018

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Time Traveler for unfaithful

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

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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 \

Kids Definition of unfaithful

: not faithful : disloyal

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