To outsmart someone means to defeat them by being cleverer rather than stronger or faster. When you outsmart an opponent, you use your intelligence and quick thinking to gain an advantage they didn't see coming.

In a game of chess, you might outsmart your friend by setting up a trap they don't notice until it's too late. A detective outsmarts a criminal by figuring out their plan before they can carry it out. In tag, you might outsmart the person who's “it” by faking one direction and then darting another way.

The word suggests using your brain strategically in competition or conflict. You can outsmart a difficult math problem by finding a creative shortcut. A mouse might outsmart a cat by squeezing through a space too small for the cat to follow.

Outsmarting someone requires you to think ahead, notice what others miss, or come up with a solution no one else considered. It's about mental quickness and cleverness applied at the right moment. When you outsmart someone, you win not through force, but through thinking better than they did.