Harlequin (noun)

1. A clown or buffoon in traditional pantomime or Commedia dell'arte, typically dressed in brightly patterned clothes and a mask.
2. A character in literature or other media that is comically inconsistent or contradictory.

Origin:

From the old french "helquin" meaning a buffoon or a clown, from the name arlecchino, a character in the commedia dell"arte. .

Examples:

1. He was dressed as a harlequin for the carnival.
2. The harlequin's antics kept the audience in stitches.
3. The harlequin character in the play was a mischievous trickster.
4. His moods were as changeable as a harlequin's costume.
5. The harlequin's colorful costume was a highlight of the parade.