What is the Latin word for treacherous?

The usual Latin words for “treacherous” are perfidus, perfidiōsus, dolōsus; also subdolus, fallō. The right choice depends on the sense; see the distinctions below.

English → Latin

“treacherous” in Latin

perfidusthat breaks one's promise; false; faithless; dishonest; disloyal; deceitful; treacherous; unsafe; dangerous perfidiōsustreacherous, perfidious dolōsuscrafty, cunning, deceitful subdoluscrafty, cunning, sly, subtle fallōto deceive, beguile, trick, cheat, delude, ensnare, disappoint; to mistake, be mistaken, deceive oneself; to escape the

Riddle & Arnold A Copious and Critical English–Latin Lexicon, 1864

treacherous

perfidus: perfidiosus: dolosus (tricky): subdolus (secretly plotting, etc.): falsus (false).

Quick answer

What is the Latin word for treacherous?: The usual Latin words for “treacherous” are perfidus, perfidiōsus, dolōsus; also subdolus, fallō. The right choice depends on the sense; see the distinctions below.

Entry from J. E. Riddle & T. K. Arnold, A Copious and Critical English–Latin Lexicon (rev. C. Anthon, New York: Harper, 1864), digitised by Fergus J. P. Walsh, CC BY-SA 4.0; Latin markup adapted by latindictionary.co.