A joker is someone who loves making jokes and getting laughs from the people around them. The class joker might crack funny comments during lessons or pull harmless pranks that make everyone giggle. While jokers can brighten up a room and help people relax, there's a time and place for jokes: being a joker during a serious moment or when others need to concentrate can be annoying rather than entertaining.

The word also refers to the wild card in a deck of playing cards, usually decorated with a picture of a court jester or clown. In many card games, the joker can substitute for any other card, making it extremely valuable. Some games remove the jokers entirely, while others make them the most powerful cards in the deck.

When someone calls another person a joker in a dismissive way (“that joker”), they mean the person isn't taking something seriously enough or isn't competent at what they're doing. If your older sibling says “some joker parked blocking our driveway,” they're expressing frustration at someone's thoughtlessness. The tone makes all the difference: being called the joker of your friend group is usually affectionate, but being called a joker in an annoyed voice means someone thinks you're not being responsible.