A jockey is someone who professionally rides horses. Jockeys usually ride horses in races. Jockeys need to be as light as possible, so the horses can run faster when they are carrying them.
A judge is someone who is in charge of a court of law, and listens to all sides of a court case, when someone has been accused of doing something bad. Judges also decide what punishment will be given to someone who is found guilty.
Outside of a law court, a judge is someone who decides who will win a competition, such as a sports game, a pet show, or an art competition.