perfidious

adjective
per·​fid·​i·​ous | \ (ˌ)pər-ˈfi-dē-əs How to pronounce perfidious (audio) \

Definition of perfidious

: of, relating to, or characterized by perfidy

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Other Words from perfidious

perfidiously adverb
perfidiousness noun

Choose the Right Synonym for perfidious

faithless, false, disloyal, traitorous, treacherous, perfidious mean untrue to what should command one's fidelity or allegiance. faithless applies to any failure to keep a promise or pledge or any breach of allegiance or loyalty. faithless allies false stresses the fact of failing to be true in any manner ranging from fickleness to cold treachery. betrayed by false friends disloyal implies a lack of complete faithfulness to a friend, cause, leader, or country. disloyal to their country traitorous implies either actual treason or a serious betrayal of trust. traitorous acts punishable by death treacherous implies readiness to betray trust or confidence. a treacherous adviser perfidious adds to faithless the implication of an incapacity for fidelity or reliability. a perfidious double-crosser

Did You Know?

We wouldn't lie to you about the history of "perfidious" - even though the word itself suggests deceitfulness. The modern English meaning of "perfidious" remains faithful to that of its Latin ancestor, perfidus, which means "faithless." English speakers have used "perfidious" to mean "treacherous" since at least 1572. One of the earliest known uses of the term can be found in Act V, scene iii of Shakespeare’s All's Well That Ends Well: the "perfidious slave" Parolles is thought to be an unreliable witness; he’ll say whatever suits his purpose, whether true or not. In contemporary usage, "perfidious" not only implies treacherousness, but an inability to be reliable or honorable.

Examples of perfidious in a Sentence

We were betrayed by a perfidious ally. a perfidious campaign worker revealed the senator's strategy to his leading rival for the nomination
Recent Examples on the Web Elena—most perfidious of all—turns her best friend’s life into a best-selling novel. Elaine Blair, The New York Review of Books, "Making Order of the Breakdown," 24 Sep. 2020 Elena—most perfidious of all—turns her best friend’s life into a best-selling novel. Elaine Blair, The New York Review of Books, "Making Order of the Breakdown," 24 Sep. 2020 Elena—most perfidious of all—turns her best friend’s life into a best-selling novel. Elaine Blair, The New York Review of Books, "Making Order of the Breakdown," 24 Sep. 2020 Giuliani claimed that Trump’s legal team had gathered hundreds of affidavits from poll watchers and election officials alleging perfidious acts. John Cassidy, The New Yorker, "Rudy Giuliani Is a Hot Mess," 20 Nov. 2020 Elena—most perfidious of all—turns her best friend’s life into a best-selling novel. Elaine Blair, The New York Review of Books, "Making Order of the Breakdown," 24 Sep. 2020 The British, who ruled Palestine under a League of Nations mandate, were particularly perfidious. Washington Post, "They survived World War II — but were left stranded in Germany," 30 Oct. 2020 Elena—most perfidious of all—turns her best friend’s life into a best-selling novel. Elaine Blair, The New York Review of Books, "Making Order of the Breakdown," 24 Sep. 2020 Elena—most perfidious of all—turns her best friend’s life into a best-selling novel. Elaine Blair, The New York Review of Books, "Making Order of the Breakdown," 24 Sep. 2020

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

1572, in the meaning defined above

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Time Traveler for perfidious

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The first known use of perfidious was in 1572

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Last Updated

30 Dec 2020

Cite this Entry

“Perfidious.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/perfidious. Accessed 28 Feb. 2021.

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More Definitions for perfidious

perfidious

adjective

English Language Learners Definition of perfidious

literary : not able to be trusted : showing that someone cannot be trusted

More from Merriam-Webster on perfidious

Thesaurus: All synonyms and antonyms for perfidious

Nglish: Translation of perfidious for Spanish Speakers

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