adj.
1. soiled with dirt; foul; unclean: dirty laundry.
2. spreading or imparting dirt; soiling: dirty smoke.
3. vile; mean; sordid; contemptible: to play a dirty trick on someone.
4. obscene; pornographic; lewd: a dirty joke.
5. undesirable or unpleasant; thankless: He left the dirty work for me.
6. very unfortunate or regrettable: That’s a dirty shame!
7. not fair or sportsmanlike; unscrupulous: a dirty fighter.
8. hostile, insulting, contemptuous, or resentful: She gave me a dirty look. He made a dirty crack about the cooking.
9. (of a nuclear weapon) producing a relatively large amount of radioactive fallout.
10. (of the weather) stormy; squally: It looks dirty to windward.
11. Informal. obtained through illegal or disreputable means: dirty money.
12. appearing as if soiled; dark-colored; dingy; murky.
13. Slang. using or in possession of narcotics.
14. Foreign Exchange. (of currency floats) manipulated, as by a central bank influencing or changing exchange rates (opposed to clean).
–verb (used with object), verb (used without object)
15. to make or become dirty.
–adverb
16. Informal. in a mean, unscrupulous, or underhand way: to play dirty.
17. Informal. in a lewd manner: to talk dirty.