1) Apostatise 2) Desert 1) Apostatise 2) Renounce 3) Repudiate 4) Tergiversate 5) To commit apostasy 
• (v. i.) To renounce totally a religious belief once professed; to forsake one`s church, the faith or principles once held, or the party to which one has previously adhered.
A·pos'ta·tize intransitive verb [ imperfect & past participle Apostatized ; present participle & verbal noun Apostatizing .] [ Late Latin apostatizare .] To renounce totally a religious belief once professed; to forsake one's chur...
[v] - abandon one`s beliefs or allegiances
apostatise verb abandon one`s beliefs or allegiances
to commit apostasy.