perfidy

American  

[pur-fi-dee] / ˈpɜr fɪ di /

noun

• perfidies
  plural

1. deliberate breach of faith or trust; faithlessness; treachery.

   perfidy that goes unpunished.

2. an act or instance of faithlessness or treachery.

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perfidy British  

/ ˈpɜːfɪdɪ /

noun

1. a perfidious act

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Synonym Usage

See disloyalty.

Other Word Forms

Noun Inflected Forms

• perfidies
  plural

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.

Example Sentences

See Examples For:

perfidy perfidies

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

Now, those who are convinced of the perfidy of cats won’t like the answers that are emerging.

From New York Times ● Nov. 12, 2022

Bristling and increasingly convinced of Western perfidy and decadence, he was in many respects a changed man.

From Seattle Times ● Mar. 26, 2022

And the owners of them, sullen faced, unrepentant, pushed by the Eyes against the walls of their bedrooms, while the sorrowful voice of the announcer tells us voice-over about their perfidy and ungratefulness.

From "The Handmaid's Tale" by Margaret Atwood

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

And yet the real reason for the plan remains unstated," said Fossbrooke, looking him steadfastly in the face, "so true is what the Spanish proverb says, 'Love has more perfidies than war.'

From Sir Brook Fossbrooke, Volume II. by Charles James Lever

It makes us forget the struggles, perfidies, intrigues, the miseries of the hours of toil and noisy activity, all the conventionalities of civilization.

From Astronomy for Amateurs by Frances A. (Frances Alice) Welby