What is the meaning of Joker?

A person who makes jokes.

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.

Something kept in reserve that can be used to gain an advantage; a trump card.

An unspecified, vaguely disreputable person.

A loser.

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.

joker (playing card)

joker (playing card)

any wild card or similar, even in non-card games

joker

wildcard

lifeline

blank tile

joker (playing card)

Alternative spelling of dżoker

Alternative form of jóquer

joker

joker

joker, trump card, something kept in reserve that can be used to gain an advantage

Source: wiktionary.org