Refers to a circus clown or a comedic performer in a clown costume. Can also be used figuratively for someone who acts foolishly or is a laughingstock.
from French pierrot
He plays the clown in the circus.
At the circus, a clown was handing out balloons.
He is the class clown.
Being used by her, I felt like I'd become a fool.
I dressed up as a clown for the kid's birthday party.