Where does “perfidious” come from?

Perfidious derives from Latin perfidiosus, formed with the suffix -osus from Latin perfidia, which combines Latin fides (faith or trust) with the prefix per- (through), ultimately from Proto-Indo-European bʰeydʰ- (to trust or persuade).

perfidious (English): Of, pertaining to, or representing perfidy;...

Definitions

  1. Of, pertaining to, or representing perfidy;...

Ancestry of “perfidious”, step by step

StepLanguageWordMeaning
1Latinperfidiōsustreacherous, perfidious
2Latinperfidiafaithlessness, dishonesty, treachery, falsehood,...
3LatinperfidusThat breaks his promise; faithless, false,...
4Latinperthrough, by means of; throughout, during
5LatinAdtoward, to
6Latinilliche, she, it, yonder, that, overthere; in that...
7Latinillethat; those; "; demonstrative pronoun "; that...
8LatinolleArchaic form of ille
9Proto-Italic*olnosthat

Words derived from “perfidious

Every word from Proto-Italic *olnos
perfidious — Etymology, Origin & Word History | Etymology Explorer