/perr"fi dee/ , n. , pl. perfidies .
1. deliberate breach of faith or trust; faithlessness; treachery: perfidy that goes unpunished.
2. an act or instance of faithlessness or treachery.
[ 1585-95; perfidia faithlessness, equiv. to perfid ( us ) faithless, lit., through (i.e., beyond the limits of) faith ( per- PER- + fid ( es ) faith + -us adj. suffix) + -ia -Y 3 ]
Syn . See disloyalty .