v. To give up or renounce one's position or belief.
the GNU version of the Collaborative International Dictionary of English
verb-intransitive. 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.
The Century Dictionary and Cyclopedia
To abandon one's profession or church; forsake one's principles; retrograde from one's faith; withdraw from one's party. Also spelled apostatise.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
v. abandon one's beliefs or allegiances
Word Usage
"To apostatize from Christ is to apostatize from the living God (Heb 2: 3)."