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

Definition of perfidious

: of, relating to, or characterized by perfidy

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 The real mystery in this perfidious tale is why the FBI decided to advance the dossier hoax to the world, thus weakening America and its presidency. WSJ, 6 June 2022 Millions of Russians with friends and relatives in Ukraine are heartsick, while others cling to the belief that Russian President Vladimir Putin is doing only what is necessary to protect the motherland against a perfidious West. Katya Korobtsova, Los Angeles Times, 1 Mar. 2022 Countries also find ways to live with them, and they can be used as a rhetorical device—unfair sanctions imposed by a perfidious West—to tighten a ruler’s grip on power. Tom Mctague, The Atlantic, 23 Feb. 2022 Thanks to that episode, and to Winston Churchill’s denunciation of the agreement, the names of Munich, Chamberlain, and appeasement have ever since been bywords for perfidious betrayal. Geoffrey Wheatcroft, The New Republic, 21 Feb. 2022 It's been Agatha all along — and her very own insidious, perfidious spinoff is now in the works. Brendan Morrow, The Week, 7 Oct. 2021 Our country surely could not countenance the injuring of more than 130 police officers (including one who subsequently died) and the perfidious calls to lynch the Republican vice president and the Democratic speaker of the House. Phillip Halpern, San Diego Union-Tribune, 16 Dec. 2021 Few would dispute the need to confront China on its perfidious treatment of its Uighur minority, not to mention various other human rights abuses in the country. Ike Brannon, Forbes, 2 Sep. 2021 The country needed a leader and much of the public and news media found it in the gruff, uncharismatic, and perfidious form of Andrew Cuomo. Alex Shephard, The New Republic, 3 Aug. 2021 See More

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.

First Known Use of perfidious

1572, in the meaning defined above

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The first known use of perfidious was in 1572

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Dictionary Entries Near perfidious

perfide Albion



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Last Updated

10 Jun 2022

Cite this Entry

“Perfidious.” Dictionary, Merriam-Webster, Accessed 30 Jun. 2022.

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More from Merriam-Webster on perfidious

Nglish: Translation of perfidious for Spanish Speakers


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