perfidy

Where does the word "perfidy" come from? It comes from Latin fides, passing through Latin before entering English (1500s).

Perfidy’s story begins in Latin: fides meant “faith, trust.” Faith, trust, combined with per- (through, used to mean against). Within Latin, it grew into perfidia by ancient. Treachery, breaking of faith, from per- and fides. It reached English by 1500s as perfidy. Settled as the English word for deceitfulness and untrustworthiness. Today, perfidy means deliberate breach of trust or faith, deceitfulness.

1. Stage 1 · Latin · ancient fides "faith, trust", faith, trust, combined with per- (through, used to mean against).
2. Stage 2 · Latin · ancient perfidia "treachery, breaking of faith", treachery, breaking of faith, from per- and fides.
3. Stage 3 · English · 1500s perfidy "deceitfulness and untrustworthiness", settled as the English word for deceitfulness and untrustworthiness.