perfidy
Americannoun
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perfidies
plural
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deliberate breach of faith or trust; faithlessness; treachery.
perfidy that goes unpunished.
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an act or instance of faithlessness or treachery.
noun
Synonym Usage
See disloyalty.
Other Word Forms
Noun Inflected Forms
Etymology
Origin of perfidy
1585–95; < Latin perfidia faithlessness, equivalent to perfid ( us ) faithless, literally, through (i.e., beyond the limits of ) faith ( per- per- + fid ( ēs ) faith + -us adj. suffix) + -ia -y 3
Explanation
If you shared your most embarrassing secrets with a friend who then told them to everyone he knows, his betrayal could be described as perfidy. The noun perfidy means "deceitfulness" or "treachery," so it's not just being mean, but deliberately betraying a trust. The Latin root of perfidy is made up of per, or "through," and fidem, or "faith." So in order for perfidy to happen, there has to have first been a sense of faith in place, which was then broken or betrayed.
Vocabulary lists containing perfidy
The Declaration of Independence
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A Web of Lies
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Excerpt from "The Declaration of Independence"
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
They will be promoted on social media and television by washed-up athletes and unscrupulous influencers paid well for their perfidy.
From MarketWatch ● Sep. 17, 2026
When his perfidy has been exposed, he says: “What you know you know. From this time forth I never will speak word.”
From The Wall Street Journal ● Jun. 1, 2026
He has persisted in insulting the leaders of these countries for failing to bail him out of his jam, writing long screeds on social media that rail against their alleged perfidy.
From Salon ● Mar. 19, 2026
But when Nikki meets him after trailing him to his fancy hotel, his elegant perfidy soon fades in the face of larger, out-and-out treachery.
From New York Times ● Apr. 2, 2021
Through the loosely placed boards in the wall floated the bark and jabber of a talk-radio show about the latest soccer perfidy from Argentina, Brazil’s hated rival.
From "1491" by Charles C. Mann
A famous essay in the Baffler, “The Problem With Music,” laid out the perfidies of the major-label system, at the time still in a post-Nirvana feeding frenzy for young rock acts.
From Los Angeles Times ● May 8, 2024
Swinton Byrne’s own reactions to her fictional lover’s perfidies were more indignant, and less compliant, than what we see onscreen as Julie’s.
From The New Yorker ● May 13, 2019
Gathering up great and infamous political speeches, his juxtapositions compare and contrast passions and perfidies with subtlety and wit, ranging across the French, Flemish, American and German tongues.
From The Guardian ● Aug. 27, 2012
The perfidies I recollect Should make me much more circumspect, Reform me both in deed and word, And this fifth canto ought to be From such digressions wholly free.
From Eugene Oneguine [Onegin] A Romance of Russian Life in Verse by Henry Spalding
His authority would at least have kept in check the discords, perfidies, and excesses to which he, probably with justice, afterward attributed the failure of the enterprise.
From Great Men and Famous Women. Vol. 5 A series of pen and pencil sketches of the lives of more than 200 of the most prominent personages in History by Charles F. (Charles Francis) Horne
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
