Pronunciation: ( jō'kur),[key] —n. 1. a person who jokes.
2. one of two extra playing cards in a pack, usually imprinted with the figure of a jester, used in some games as the highest card or as a wild card.
3. U.S. Politics.a clause or expression inserted in a legislative bill with the unavowed object of defeating the ostensible purpose of the bill if passed.
4. a seemingly minor, unsuspected clause or wording that is put into an agreement, legal document, etc., to change its effect.
5. an unexpected or final fact, factor, or condition that changes or reverses a situation or result completely: He gave her a beautiful diamond engagement ring, but the joker was that it was stolen! 6. any method, trick, or expedient for getting the better of another: They pulled a joker on us to get better seats. 7. Informal.a man; fellow; chap: That joker is earning twice as much as I am. 8. a person who thinks he or she is very funny; prankster: Who's the joker who frosted the cake with shaving cream? 9. Informal.a wise guy; wiseacre; smart aleck: Tell that joker to stop using my parking space.