noun
Refers specifically to the joker card in a deck of playing cards.
トランプのジョーカーは、どのカードの代わりにも使える。
The joker in a deck of cards can be used in place of any other card.
noun
Used for a person who jokes around or is the life of the party; can be affectionate or mildly critical depending on context.
彼はクラスのジョーカーで、いつもみんなを笑わせている。
He's the class joker and always makes everyone laugh.