To sweat means to release moisture through your skin when your body heats up. Your body produces sweat to cool itself down, like how water evaporating from your skin after swimming makes you feel chilly. When you run around at recess or play sports on a hot day, you'll notice droplets forming on your forehead and arms. That's your body's cooling system at work.

People also sweat when they're nervous or scared. Before giving a presentation to the class, you might notice your palms getting sweaty even though you haven't been running. That's your body reacting to stress.

The word has other meanings too. When someone says “don't sweat it,” they mean don't worry about it or don't stress over something small. If you forget to bring a pencil to class, a friend might say “don't sweat it” while handing you an extra one.

Sweat can also mean hard work and effort. When a coach talks about the sweat the team put into practice, or when someone says a project took “blood, sweat, and tears,” they're talking about intense effort and dedication. The related phrase “sweat equity” describes the value of hard work someone puts into building or improving something, like when you help paint your tree house and earn ownership through your labor instead of money.