Joker
Joker , noun
1.
One who makes jokes or jests.
2.
(Card Playing) See Best bower, under 2d Bower.
3.
(Card Playing) An extra card usually included in a deck of playing cards, having the same design as the others on the back, but on the face having a picture of a jester. It is not included in the deck used in most games, but in certain games may be included and then takes on a special value, such as the highest-valued card, or a wild card.
4.
A clause placed in a document, such as a contract or a piece of legislation, not itself appearing significant, but in a subtle way substantially changing the effect of the document.
5.
Any fact or condition which is unknown or not apparent, which reverses an apparently advantageous position; a kicker.
6.
A person; a fellow; a chap; -- usually used in a mildly disparaging sense; as, who's the joker who left the ice cream on the table?.