IPA: //ˌmɪs.bɪˈheɪ.vər//
KK: /mɪsˈbiːhævər/
A person who behaves badly or inappropriately.
The teacher had to speak to the misbehaver about his actions in class.
Misbehaver → It is formed from "mis-" (meaning wrongly or badly) and "behave" (from Old French *behaivare*, meaning to conduct oneself). The word "misbehaver" refers to someone who conducts themselves in a wrong or bad manner.
Think of someone acting 'wrongly' ('mis-') in their 'conduct' ('behave') — that's why a misbehaver is someone who behaves badly.
No commonly confused words.