joker

plural jokers

1. A person who makes jokes.
2. slangA funny person.
3. A jester.

   Synonyms: court jester, fool, 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. figurativelySomething 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.'

   2008 September 18, Ian Rankin, The Hanging Garden: The #1 bestselling series that inspired BBC One’s REBUS, Hachette UK, →ISBN

   2 more examples

   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.'

   2012 January 1, Simon Packham, Silenced, Bonnier Publishing Fiction Ltd., →ISBN

   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.

   2016 October 17, Dipo Adesida, My French Teacher Had an Igbo Accent: An Inspiring Collection of Memories, Memoirs and Mischiefs, Partridge Africa, →ISBN

6. An unspecified, vaguely disreputable person.

   Some joker keeps throwing eggs at my windows.

   Synonyms: clown

   1. A loser.

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

      Synonyms: clown

7. New ZealandcolloquialA man.
8. A clause in a contract that undermines its apparent provisions.

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

   1939, Canadian Parliament, Official Report of Debates, House of Commons, volume 218, page 858

   3 more examples

   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.

   1922, Farm Machinery and Equipment, page lxxxiii

   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.

   1942, Billboard, volume 54, number 41, page 5

   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.

   1958, Duncan Leroy Kennedy, Bill drafting, page 12

9. governmentA friendly unit that acts as a suspected hostile unit in a military exercise.

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

   1998, APP-6A: Military Symbols for Land-Based Systems, page 9

10. 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.

11. board gamesA 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.

    2018 October 12, aabicus, “My 7 Favorite Fairy Chess Pieces”, in The Daily SPUF

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.

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

   2015, Manuel Luis Martinez, Drift: A Novel, page 16

   4 more examples

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

   2007, Joe Layden, The Last Great Fight, page 217

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

   2008, Deborah Eden, The Destroyer, page 82

   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.

   2011, Steve Hely, How I Became a Famous Novelist, page 185

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

   2014, Tania Carver, The Doll's House, page 22