- deliberately faithless; treacherous; deceitful: a perfidious lover.
Origin of perfidious
SynonymsSee more synonyms for perfidious on Thesaurus.com
false, disloyal; unfaithful, traitorous.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for perfidiousness
Third, Munayyer references Plan Dalet as an example of Zionist perfidiousness, a “military plan for the conquest of Palestine.”(Mis)Interpreting Zionist History
Brent E. Sasley
March 19, 2013
Saith Q. Curtius, Perfidiousness is a crime which no merits can mitigate.A Christian Directory
This was by perfidiousness to draw her into a snare to her undoing.A Christian Directory (Part 2 of 4)
Again he had a sad proof of the perfidiousness of Europeans.The Life and Labours of the Rev. Samuel Marsden
She once went so far as to say, that it was not superior discernment, which enabled her to suspect the perfidiousness of Walter.The Loyalists, Vol. 1-3
Sabine's eyes opened upon new vistas of man's perfidiousness.Cape Breton Tales
Harry James Smith
- guilty, treacherous, or faithless; deceitful
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 perfidiousness
1590s, from Latin perfidiosus "treacherous," from perfidia (see perfidy). Related: Perfidiously; perfidiousness.
Online Etymology Dictionary, © 2010 Douglas Harper