Definition of behave behaved; behaving transitive verb 1 : to manage the actions of (oneself) in a particular way 2 : to conduct (oneself) in a proper manner getting children to behave themselves intransitive verb 1 : to act, function, or react in a particular way He behaves like a child. testing how various metals behave under heat and pressure 2 : to conduct oneself properly Please behave. — behaver noun See behave defined for English-language learners See behave defined for kids Examples of behave in a Sentence If you can't behave in the store we'll have to leave. If you can't behave yourself in the store we'll have to leave. I wish those children would behave themselves. He behaves like a child! The experiment tested how various metals behave under heat and pressure.