Dictionary.com

perfidious

[ per-fid-ee-uhs ]
/ pərˈfɪd i əs /
Save This Word!
See synonyms for: perfidious / perfidiously / perfidiousness on Thesaurus.com
adjective
deliberately faithless; treacherous; deceitful: a perfidious lover.
QUIZ
CAN YOU ANSWER THESE COMMON GRAMMAR DEBATES?
There are grammar debates that never die; and the ones highlighted in the questions in this quiz are sure to rile everyone up once again. Do you know how to answer the questions that cause some of the greatest grammar debates?
Question 1 of 7
Which sentence is correct?
His boss, whom he admires, is waiting to meet with him about the big project.
His boss, who he admires, is waiting to meet with him about the big project.
TAKE THE QUIZ TO FIND OUT

Origin of perfidious

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

OTHER WORDS FROM perfidious

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Words related to perfidious

betraying, deceitful, deceptive, double-crossing, double-dealing, faithless, false, insidious, misleading, recreant, shifty, slick, snake in the grass, traitorous, two-faced, two-timing, undependable, unfaithful, unloyal, unreliable

How to use perfidious in a sentence

British Dictionary definitions for perfidious

perfidious
/ (pəˈfɪdɪəs) /
adjective
guilty, treacherous, or faithless; deceitful

Derived forms of perfidious

perfidiously, adverbperfidiousness, 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
FEEDBACK