Definitions

from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun Deliberate breach of faith; calculated violation of trust; treachery.
  • noun The act or an instance of treachery.

from The Century Dictionary.

  • noun Breach of faith or trust; base treachery; faithlessness.
  • noun Synonyms See perfidious.

from the GNU version of the Collaborative International Dictionary of English.

  • noun The act of violating faith or allegiance; violation of a promise or vow, or of trust reposed; faithlessness; treachery.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun A state or act of violating faith or allegiance; violation of a promise or vow, or of trust reposed; faithlessness; treachery.
  • noun law Specifically, in warfare, an illegitimate act of deception, such as using symbols like the Red Cross or white flag to gain proximity to an enemy for purposes of attack.
  • noun A state or act of deceit.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun an act of deliberate betrayal
  • noun betrayal of a trust

Etymologies

from The American Heritage® Dictionary of the English Language, 4th Edition

[Latin perfidia, from perfidus, treacherous : per-, to destruction; see per– + fidēs, faith; see bheidh- in Indo-European roots.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Latin perfidus ("faithless, treacherous, false"), from fides ("faith"); related to, for example, English fidelity.

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Examples

  • But much as she loved England she was very loud in denouncing what she called the perfidy of the mother to the brightest of her children.

    Tales of all countries 2004

  • One that routinely engages in perfidy, intentionally targets civilians, uses hospitals, schools and mosques to hide and fire rockets, transports its soldiers and material using ambulances marked with the red crescent, refuses to abide by a unified command structure, refuses to wear distinctive insignia, .... is not comparable to a “freedom fighter” in any respect except the trivial.

    The Volokh Conspiracy » What’s Going on With Turkey 2010

  • The day the nadir of his perfidy is brought to light, he will effectively have put the lives of hundreds of thousands — maybe even millions of Americans and more worrisome to him — American Interests (“Cha-CHING!”) in exponentially greater jeopardy than before.

    Look 'Pon The Devil's Brow...An Impossibility... 2009

  • I await the response of someone that believes that perfidy is acceptable in killing Mr. Awlaki.

    The Volokh Conspiracy » Opinio Juris Discussions of Targeting of US Citizen 2010

  • The day the nadir of his perfidy is brought to light, he will effectively have put the lives of hundreds of thousands — maybe even millions of Americans and more worrisome to him — American Interests (“Cha-CHING!”) in exponentially greater jeopardy than before.

    Archive 2009-09-01 2009

  • In my readings of British history generally, the word perfidy arises quite often.

    On Thursday, the Legg report will be published along with... 2008

  • In my readings of British history generally, the word perfidy arises quite often.

    On Thursday, the Legg report will be published along with... 2008

  • It would be naive to think that human perfidy is not capable of depriving some of its members of these ingredients so that they can do no more and must depart.

    Death, Legal and Illegal 1974

  • Beria was more treacherous, more practiced in perfidy and cunning, more insolent and single-minded, than my father.

    Twenty Letters to a Father 1969

  • Beria was more treacherous, more practiced in perfidy and cunning, more insolent and single-minded, than my father.

    Twenty Letters to a Father 1967

Comments

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  • other means than his perfidy would have operated

    February 11, 2014

  • an act of deliberate betrayal; a breach of a trust

    Sure, he was the best salesman in the company; but Michael had abused the trust of the firm, sharing product secrets with a competitor, and for such perfidy he was terminated.

    October 15, 2016