CLOWN

clown [countable]

1 someone who wears funny clothes, a red nose, bright make-up on their face etc, and does silly things to make people laugh, especially at a circus

2 someone who often makes jokes or behaves in a funny way:

Frankie's a bit of a clown.

class clown (=someone in a school class who behaves in a funny or silly way)

3 a stupid or annoying person:

I can't understand what she sees in that clown.

Definition from the Longman Dictionary of Contemporary English
Advanced Learner's Dictionary