From Longman Dictionary of Contemporary Englishapostasya‧pos‧ta‧sy /əˈpɒstəsi $ əˈpɑː-/ noun [uncountable] formalRRRELIGION when someone suddenly stops believing in a religion or supporting a political party
Examples from the Corpus
apostasy• They include theft, adultery and fornication, wine drinking, highway banditry, apostasy to of the faith and rebellion.• His apostasy had cost him his empire.• His apostasy was repulsive to the Xerox people.Origin apostasy (1300-1400) Late Latin apostasia, from Greek, from aphistasthai “to revolt”, from apo- ( → APOCALYPSE) + histasthai “to stand” 