To relax means to become less tense, worried, or tight. When you relax your muscles after holding them stiff, they soften and loosen. When you relax your mind after concentrating hard on homework, you let go of that focused intensity and give yourself a mental break.

Relaxation happens in different ways. Your body relaxes when you stop clenching your jaw or drop your shoulders from up near your ears. Your mind relaxes when you stop worrying about tomorrow's presentation and lose yourself in a good book instead. A strict teacher might relax the rules on the last day of school, making them less rigid.

The word suggests a kind of easing or unwinding. After a tough soccer practice, your coach might tell everyone to relax and catch their breath. When someone tells you to relax, they're usually noticing you seem stressed or overly serious about something. Sometimes people say “Relax!” to mean “calm down” or “don't worry so much.”

The opposite of relaxing is tensing up or staying rigid and anxious.