joker

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. One who tells or plays jokes.
2. n. An insolent person who seeks to make a show of cleverness.
3. n. Informal An annoying or inept person: Some joker is blocking my driveway.
4. n. Games A playing card, usually printed with a picture of a jester, used in certain games as the highest-ranking card or as a wild card.
5. n. A minor clause in a document such as a legislative bill that voids or changes its original or intended purpose.
6. n. An unforeseen but important difficulty, fact, or circumstance.
7. n. A deceptive means of getting the better of someone.

Century Dictionary and Cyclopedia

1. n. One who jokes, in speech or in deed; a jester; a merry fellow.
2. n. A playing-card, either blank or having some comical or other special device, added to a pack, and used in some games, as in euchre. It is always a trump, and generally the highest trump. Often called jolly joker.
3. n. Figuratively, something concealed that wins the game; a trick under an innocent guise: as, a joker in a legislative bill.

Wiktionary

1. n. A person who makes jokes.
2. n. slang A funny person.
3. n. A jester.
4. n. 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. n. An unspecified, vaguely disreputable person.
6. n. New Zealand, colloquial A man.

GNU Webster's 1913

1. n. One who makes jokes or jests.
2. n. (Card Playing) See Best bower, under 2d Bower.
3. n. (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. n. 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. n. Any fact or condition which is unknown or not apparent, which reverses an apparently advantageous position; a kicker.
6. n. A person; a fellow; a chap; -- usually used in a mildly disparaging sense.

WordNet 3.0

1. n. an inconspicuous clause in a document or bill that affects its meaning in a way that is not immediately apparent
2. n. a person who enjoys telling or playing jokes
3. n. a playing card that is usually printed with a picture of a jester
4. n. a person who does something thoughtless or annoying