joker
n. countablen. a person who likes to tell jokes or play tricks on others. It can also be a rude way to describe someone you think is annoying or foolish.
n. a person who habitually jokes or plays pranks; also used as a mildly pejorative term for a person considered foolish, incompetent, or annoying. Often used in British English to dismiss someone's seriousness or authority.
He is the office joker and always makes us laugh.
Some joker left a fake spider on my desk, and I nearly jumped out of my chair.
The manager dismissed the consultant as a joker who had no real understanding of how the manufacturing floor actually operated on a daily basis.
From joke + -er, but in the sense of a playing card possibly by alteration of Jucker, also the origin of the name of the card game euchre.
Commonly used with the definite article ('the joker') when identifying a specific person in a group known for humor.