To cheat means to act dishonestly to gain an unfair advantage. When someone cheats on a test, they might sneak looks at another student's answers instead of relying on their own knowledge. When a player cheats in a board game, they might move extra spaces when no one's watching or hide cards they're not supposed to have.

Cheating is different from making an honest mistake or losing fair and square. A cheater knows the rules but chooses to break them secretly, hoping others won't notice. Someone might cheat at cards, cheat on their taxes, or cheat in a race by taking a shortcut.

People sometimes say they feel cheated when something seems unfair, like being cheated out of a deserved victory. A cheater is someone who cheats regularly or habitually. As a noun, a cheat can also be a person who cheats.