Defining Apostasy

Via Markus Oehler comes this definition of apostasy from a work by B. J. Oropeza

The phenomenon that occurs when a religious follower or a group of followers turn away from or otherwise repudiate the central beliefs and practices they once embraced in a respective religious community.

The Greek term apostasia simply means rebellion, revolt, and it was not necessarily religious. There is much, however, to commend this definition.