APOSTASY, a term generally employed to describe a com plete renunciation of the Christian faith, or even an exchange of one form of it for another, especially if the motive be unworthy. In the first centuries of the Christian era, apostasy was most commonly induced by persecution, and was indicated by some out ward act, such as offering incense to a heathen deity or blasphem ing the name of Christ. In the Roman Catholic Church the word is also applied to the renunciation of monastic vows (apostasis a monachatu), and to the abandonment of the clerical profession for the life of the world (apostasis a clericatu) .