APOSTATIZE

apostatize, apostatise, tergiversate

(verb) abandon one’s beliefs or allegiances

Source: WordNet® 3.1

Etymology

Verb

apostatize (third-person singular simple present apostatizes, present participle apostatizing, simple past and past participle apostatized)

To give up or renounce one's position or belief.

Source: Wiktionary

A*pos"ta*tize, v. i. [imp. & p. p. Apostatized; p. pr. & vb. n. Apostatizing.] Etym: [LL. apostatizare.]

Definition: 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. He apostatized from his old faith in facts, took to believing in Carlyle.

Source: Webster’s Unabridged Dictionary 1913 Edition