[ pur-fi-dee ]
/ ˈpɜr fɪ di /

noun, plural per·fi·dies.

deliberate breach of faith or trust; faithlessness; treachery: perfidy that goes unpunished.
an act or instance of faithlessness or treachery.

Nearby words

  1. perfector,
  2. perfector press,
  3. perfervid,
  4. perfidious,
  5. perfidiously,
  6. perfin,
  7. perfing,
  8. perfoliate,
  9. perfoliate bellwort,
  10. perforate

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 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for perfidy

British Dictionary definitions for perfidy


/ (ˈpɜːfɪdɪ) /

noun plural -dies

a perfidious act

Word Origin for perfidy

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

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