/ Dictionary / Index P perfidy: Meaning and Definition of Find definitions for: per•fi•dy Pronunciation: (pûr'fi-dē), [key] — pl. -dies. deliberate breach of faith or trust; faithlessness; treachery: perfidy that goes unpunished. an act or instance of faithlessness or treachery. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: perfidy (Thesaurus) perfidious perfin Related Content Daily Word Quiz: deleterious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language