Other forms: misbehaved; misbehaving; misbehaves
When you misbehave, you do something bad. One way to misbehave would be to stand on the roof of your house and throw water balloons at people walking by.
Kids are probably most often said to misbehave, although adults misbehave at least as often. A bank executive, for example, might misbehave by embezzling money, and a politician misbehaves when she lies under oath. The meaning of the word is clear once you know that the prefix mis- means "bad or wrong," from Old English. When you combine it with behave, you get bad behavior.