(おちゃめ) A class clown – someone who does pranks, impersonates people, is mischievous. Can be used of kids and adults. Does not have a bad connotation.
やんちゃ Often translated as ‘mischievous’ but is more like ‘unpredictable.’ A funny person that can turn violent or take a joke too far. Can be used of kids and adults, and has a little bad meaning to it.