Nasty is an English adjective with multiple meanings depending on context:
1. Very bad or unpleasant: "That's a nasty cut you've got there."
2. Mean or spiteful: "Don't be so nasty to your little sister!"
3. Sexually explicit or offensive: "He made some nasty comments."
4. Difficult to deal with: "This is a nasty problem to solve."
5. (Slang) Extremely good or impressive: "That dunk was nasty!"