- Today's Word
Perfidious
Perfidious
per-FID-ee-uhs
Definition
(adjective) Deceitful and untrustworthy; deliberately disloyal.
Example
His perfidious actions during the negotiation shocked even his rivals.
Word Origin
Late Middle English: from Old French perfidieux, from Latin perfidiosus, from perfidia ‘treachery’, based on per- ‘through’ + fides ‘faith’.
Fun Fact
Perfidious isn’t your average insult. It suggests a deep and knowing betrayal, often by someone who pretended to be loyal. Historically, it was used in diplomacy and politics—perfidious Albion was a nickname used by the French to accuse Britain of double-dealing. It shows up in literature, courtroom speeches, and bitter breakups. This isn’t just someone who disappointed you—it’s someone who knew exactly what they were doing.