APOSTASY Meaning of APOSTASY in English [ ə'pɒstəsi ]■ noun the abandonment or renunciation of a belief or principle.OriginME: from eccles. L. apostasia , from late Gk alt. of Gk apostasis 'defection'. Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004