A traditional comic character in pantomime and Commedia dell'arte, originally in the late 1600s. Harlequin wears a black mask and brightly-colored, diamond-patterned tights. Sometimes, Harlequin carries a wooden wand or sword. The standard Harlequin is often a street performer, doing tricks, stunts, and gags for a crowd of people in public.

Also, any clown. Well, not any clown. Not Bozo, fer instance.