Concepts related to laws and rules, from both sides - justice and crime.
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.
A police officer (or policeman, policewoman or just police) is someone who makes sure that other people are obeying the law, and catches people who aren't.
Punishments are always unpleasant, and usually are tailored to fit the crime.
The opposite of punishment is reward.
A reward is something you get given if you do something well. Rewards are often given to encourage people to do something good.
The opposite of reward is punishment.