perfidious

[ per-fid-ee-uhs ]
See synonyms for: perfidiousperfidiouslyperfidiousness on Thesaurus.com

adjective
  1. deliberately faithless; treacherous; deceitful: a perfidious lover.

Origin of perfidious

1
First recorded in 1530–40; from Latin perfidiōsus “faithless, dishonest”; cf. perfidy, -ous

Other words for perfidious

Opposites for perfidious

Other words from perfidious

  • per·fid·i·ous·ly, adverb
  • per·fid·i·ous·ness, noun
  • un·per·fid·i·ous, adjective
  • un·per·fid·i·ous·ly, adverb
  • un·per·fid·i·ous·ness, noun

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use perfidious in a sentence

  • How dreadful, then, is it for sinners to speak to God perfidiously!

  • Among these captives was young Gustavus Vasa, who, thus perfidiously taken, was cruelly confined.

  • For it was long believed that Delauney had admitted the people into the first court, and then had perfidiously shot them down.

    Lectures on the French Revolution | John Emerich Edward Dalberg-Acton
  • The Baron could, by a single word perfidiously repeated, injure him very much with Alba's mother.

    Cosmopolis, Complete | Paul Bourget
  • On the testimony of his own letters it is clear he did not mind how tortuously and perfidiously he worked.

    Sir Walter Ralegh | William Stebbing

British Dictionary definitions for perfidious

perfidious

/ (pəˈfɪdɪəs) /


adjective
  1. guilty, treacherous, or faithless; deceitful

Derived forms of perfidious

  • perfidiously, adverb
  • perfidiousness, noun

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