a prankster or show-off.
jokester, clown, trickster, jester, prankster, fool, mime, buffoon, comedian, comic, entertainer, humorist, actor, satirist, madcap, antic, harlequin, wag, joker, wit
Origin of cutup
First recorded in 1775–85; noun use of verb phrase cut up
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019