What is apostasy? Dictionary.com a total desertion of or departure from one's religion, principles, party, cause, etc. Etymonline.com late 14c., "renunciation, abandonment or neglect of established religion," from Late Latin apostasia, from later Greek apostasia for earlier apostasis "revolt, defection," literally "a standing off," from apostanai "to stand away" (see apostate (n.)). General (non-religious) sense … Continue reading Apostasy