perfidious

[ per-fid-ee-uhs ]

adjective

1. deliberately faithless; treacherous; deceitful:

   a perfidious lover.

   Synonyms: traitorous, unfaithful, disloyal, false

   Antonyms: faithful

perfidious

/ pəˈfɪdɪəs /

adjective

1. guilty, treacherous, or faithless; deceitful

Derived Forms

• perˈfidiously, adverb
• perˈfidiousness, noun

Other Words From

• 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

Word History and Origins

Origin of perfidious¹

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

Example Sentences

“Behold, campers, this vile and destructive creature! This killer of songbirds! This murderer of chipmunks! This perfidious predator!”

From Literature

It ranges from Catholics who want more incense, to Latin Mass adherents who have brought back ancient prayers that mention “the perfidious Jew.”

From Seattle Times

Russian President Vladimir Putin's playing a "perfidious" game that "we must not fall for", said Defence Minister Boris Pistorius this week.

From BBC

“If the initial findings are confirmed, it will be a perfidious attack on our electricity infrastructure,” Stübgen said.

From Seattle Times

Not that the court will hold that Trump is immune from the charges growing out of his perfidious attempts to overturn the results of the 2020 eleciton.

From Los Angeles Times