Dirty means covered with or containing dirt, mud, stains, or other unwanted substances. Your hands get dirty when you've been digging in the garden or working on an art project. A plate is dirty after you've eaten from it, covered with crumbs and sauce.

The word also describes something that isn't clean or pure in other ways. Dirty water has pollutants or sediment mixed into it. Dirty air contains smoke, dust, or other particles that make it unhealthy to breathe. A room becomes dirty when trash accumulates or dust settles on everything.

Dirty can describe unfair or dishonest actions too. Playing dirty in sports means breaking the rules or trying to hurt opponents. A dirty trick is a sneaky, dishonest way to get what you want, like spreading rumors about someone to make yourself look better. Fighting dirty means using tactics that are wrong or forbidden, like hitting below the belt in boxing.

The word sometimes describes something inappropriate or crude, like a dirty joke that isn't suitable for school. Dirty work refers to unpleasant tasks nobody wants to do, like cleaning out a muddy basement.

When something looks dirty, it appears unclean or worn. When someone plays dirty, they're cheating or being unfair. When the weather is dirty, it's stormy and unpleasant.