/ Dictionary / Index A apostasy: Meaning and Definition of Find definitions for: a•pos•ta•sy Pronunciation: (u-pos'tu-sē), [key] — pl. -sies. a total desertion of or departure from one's religion, principles, party, cause, etc. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: apostasy (Thesaurus) apospory apostate Related Content Daily Word Quiz: cautious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language