Keywords: joke, gag, joker, jest
As a Noun
Something that is said or done to make you laugh, for example a funny story. English = joke, gag.
A person who tells jokes. English = joker.
In a pack of cards, a card which does not belong to any of the four suits. English = joker.
As a Verb or Adjective
To tell funny stories or say things that are amusing or not serious. English = joke. Formal English = jest.
To make fun of people in a gentle but slightly cruel way, especially by telling them things which are not true which they believe. Idiomatic English = pull someone's leg.