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[pur-fi-dee] /ˈpɜr fɪ di/
noun, plural perfidies.
deliberate breach of faith or trust; faithlessness; treachery:
perfidy that goes unpunished.
an act or instance of faithlessness or treachery.
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 -y3
Synonym Study
See disloyalty. Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for perfidy
Contemporary Examples
Historical Examples
  • My shame I might bear; I might wash it out in blood at the battle's front; but my perfidy!

    The Cavalier George Washington Cable
  • His not having spoken of marriage may add to his perfidy, but can be no excuse for his conduct.

    The Contrast Royall Tyler
  • We had another instance, about this time, of the perfidy of Harlay.

  • The king and his mother were mortified by these evidences that their perfidy was suspected.

    Henry IV, Makers of History John S. C. Abbott
  • For even Delilah was a Philistine, and by her perfidy served her country.

    The Wild Geese Stanley John Weyman
  • No, Sir; but, lawyer as I am, there are depths of perfidy I'm not prepared for.

    Luttrell Of Arran Charles James Lever
  • Most of them knew Tom Harris, and they regarded his neglect of them as perfidy.

  • The fearfulness of Gibson's perfidy was almost incomprehensible.

    Spring Street James H. Richardson
British Dictionary definitions for perfidy


noun (pl) -dies
a perfidious act
Word Origin
C16: from Latin perfidia, from perfidus faithless, from per beyond + fidēs faith
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for perfidy

1590s, from Middle French perfidie (16c.), from Latin perfidia "faithlessness, falsehood, treachery," from perfidus "faithless," from phrase per fidem decipere "to deceive through trustingness," from per "through" (see per) + fidem (nominative fides) "faith" (see faith).

[C]ombinations of wickedness would overwhelm the world by the advantage which licentious principles afford, did not those who have long practiced perfidy grow faithless to each other. [Samuel Johnson, "Life of Waller"]

Online Etymology Dictionary, © 2010 Douglas Harper
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