Behaving badly is an action that goes against accepted social norms and can be expressed in a variety of ways. The crossword solutions for the term 'behave badly' include SIN (3 letters), ERR (3 letters), ACT (3 letters), misact (6 letters), actup (5 letters), and actout (6 letters). SIN is an immoral or wicked ACT, while ERR is to make a mistake or do something wrong. ACT is to do something, while misact is to do something wrong or incorrectly. Actup is to behave in a disruptive manner, and actout is to express oneself through behavior that is inappropriate or unacceptable.