joker

noun

1. A person who makes jokes.
2. (slang)A funny person.
3. A jester.
4. 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.
5. (figuratively)Something kept in reserve that can be used to gain an advantage; a trump card.

   “Rebus decided to use their joker. 'Mr Lintz made a phone call to this office. He was talking for over twenty minutes.'”

   “Tash Wilson played her 'joker' , pulling her chair so close our legs were almost touching. 'Hey, Chris, do you want to go out sometime? All you've got to do is say the word.'”

   “The director made me understand that my bubble of stardom could burst just as soon as it had been inflated if I didn't watch my attitude. Then he used his joker. I had an understudy so if I messed up or tried to create a scene, I would be summarily replaced.”

6. An unspecified, vaguely disreputable person.

   “Some joker keeps throwing eggs at my windows.”

7. An unspecified, vaguely disreputable person.

   “Don't waste your breath on these jokers round here.”

8. (New-Zealand, colloquial)A man.
9. A clause in a contract that undermines its apparent provisions.

   “Discussion of contracts and the many provisions contained therein led to a vote making it the sense of the convention that manufacturers should use a simple sales contract, free from jokers.”

   “Then, sir, on page 12 of the agreement there is a joker clause, which provides for payments in addition to the ten per cent, […]”

   “Stone claimed that there was a Joker in the contract, one clause (No. 2) calling for two weeks' notice and another (No. 8) calling for payment on a par-day basis after the first two weeks.”

   “The object of these provisions is to prevent insertion of "jokers" or "sleepers" in bills and securing passage under the false color of the title.”

10. A friendly unit that acts as a suspected hostile unit in a military excercise.

    “Joker - A friendly track or contact acting as a "suspect" track for exercise purposes only. (STANAG 1241)”

11. The option, in a pub quiz, of selecting one particular round in which one's team will score double points.

    “We used our joker as soon as the topic of sports was announced, since we are sport experts.”

12. A fairy chess piece that moves like the last piece that was moved by the opponent.

    “The problem is that it would be difficult to use a joker offensively since you could never know how it was going to move, meaning it’d be most useful setting it up for potential queen/rook captures to disincentivize your opponent from moving those pieces.”

name

1. A fictional villain of DC Comics, noted for his insanity and cunning, who either wears clown makeup or is disfigured to appear as such, and who is archenemy of Batman.

   “...grinning like the Joker, Batman's nemesis, a character described in the story as being a favorite of Douglas's.”

   “He started to laugh that maniacal laugh that sounded like the Joker on speed.”

   “I would've liked to have learned more, but the lady working the booth was a monstrous titan with dyed black hair, about ten rings on each hand, and a mouth like the Joker (Jack Nicholson version), and she spooked me.”

   “Wide and taut, fixed and immobile. Like the Joker from Batman, he thought. Or one of his victims.”

   “He looks like the Joker, the Latino one, what was his name? Cesar Romero.”