Meaning

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. An unspecified, vaguely disreputable person.
6. An unspecified, vaguely disreputable person.
7. (colloquial) A man.
8. A clause in a contract that undermines its apparent provisions.
9. A friendly unit that acts as a suspected hostile unit in a military excercise.
10. The option, in a pub quiz, of selecting one particular round in which one's team will score double points.