joker

A person who makes jokes.
(slang) A funny person.
A jester.
A playing card that features a picture of a joker (that is, a jester) and that may be used as a wild card in some card games.
(figuratively) Something kept in reserve that can be used to gain an advantage; a trump card.
An unspecified, vaguely disreputable person.
An unspecified, vaguely disreputable person.
(New-Zealand, colloquial) A man.
A clause in a contract that undermines its apparent provisions.
A friendly unit that acts as a suspected hostile unit in a military excercise.
The option, in a pub quiz, of selecting one particular round in which one's team will score double points.
A fairy chess piece that moves like the last piece that was moved by the opponent.