1. abandoning or renouncing a religious faith, political belief, or cause that one previously held
Usage: British spelling; American spelling is 'apostatizing'; present participle or gerund form of 'apostatise'

Examples

• He was accused of apostatising from the church after decades of membership.
• The politician faced criticism for apostatising his earlier environmental stance.
• Apostatising from one's faith is a serious matter in many religious communities.
• She regretted apostatising the principles she had once fought for.
• The movement condemned members for apostatising and joining rival organizations.
• Historical records show many nobles apostatising during the religious upheaval.