Cheating happens when someone breaks rules or lies.
Cheating can be done in many ways. Some students cheat on a test by copying someone else's answers and writing secret notes. This can get them kicked out of school.
People who break the rules of a game are cheating. For example, if someone holds the ball when playing soccer, they are cheating. Another form of cheating in sport is using performance-enhancing drugs; Ben Johnson and Lance Armstrong are examples of sportspeople who used drugs to cheat.
When someone is in a relationship with another person and they kiss, date or have sex with someone else, they are cheating on the person they are in a relationship with - unless they are in an open relationship.
Local and national governments have laws. If someone breaks the law, they can be punished. If someone cheats in a way that is not illegal, they cannot be punished by law. Some common punishments include jail and fines.
Organizations, such as schools, can have rules. Rules are not laws, but people can still be punished for breaking a rule.