To misbehave means to act in a way that breaks rules or goes against what's expected of you. When a student misbehaves in class, they might talk when they should be listening, ignore the teacher's instructions, or disturb others who are trying to work. When a younger sibling misbehaves at dinner, they might throw food, refuse to sit still, or make loud noises on purpose.

Misbehaving usually describes less serious rule-breaking: a student who misbehaves might get a warning or lose recess, while someone who does something truly harmful has gone beyond mere misbehavior.

Notice that misbehaving is different from making an honest mistake. If you accidentally knock over your milk, that's not misbehaving. But if you pour it on the floor on purpose, that's misbehavior. The word suggests you knew better but chose to act that way anyway. Parents, teachers, and other adults often tell children not to misbehave because following reasonable rules helps people get along.