IPA: //ˌmɪs.bɪˈliː.vər//
KK: /mɪsˈbɪlɪvər/
A person who holds incorrect beliefs or follows a false religion.
The misbeliever struggled to find the truth amidst conflicting teachings.
Misbeliever → It is formed from "mis-" (meaning wrongly) and "believer" (from "believe" which comes from Old English "beliefan", meaning to have faith or confidence). The word "misbeliever" refers to someone who holds a belief that is considered wrong or erroneous.
Think of someone who believes something 'wrongly' ('mis-') — that's why a misbeliever is someone who holds a mistaken belief.