Apostacize is an uncommon word that means to renounce or abandon one's religious beliefs or political affiliations. Some antonyms for apostacize can include "cling to," "adhere," "defend," and "support." To cling to something is to hold onto it tightly and not let it go. Adhering to a belief system is the act of staying with one's beliefs and principles. Defending a belief system is the act of protecting it from criticism or attack. Supporting a certain philosophy or religion is to give it encouragement and help it thrive. These words can be used to describe the opposite of apostacizing, which involves standing fast in one's beliefs and not abandoning them.