adjective dirtier dirt′i·er, dirtiest dirt′i·est

1. soiled or soiling with dirt; unclean
2. causing one to be soiled with dirt a dirty occupation
3. lacking luster or brilliance; dull, grayish, etc. a dirty green
4. obscene; pornographic dirty jokes
5. given to lechery or lustful thoughts; prurient a dirty mind, dirty old man
6. disagreeable or contemptible; mean; nasty a dirty coward
7. unfair; dishonest; unsportsmanlike a dirty player
8. unkind; malicious or malevolent dirty remarks
9. ☆ producing much fallout: said of nuclear weapons
10. revealing anger or irritation a dirty look
11. squally; rough dirty weather
12. ☆ Slang rasping, reedy, rough, etc. in tone a dirty trumpet

Etymology: ME dritti

transitive verb, intransitive verb dirtied dirt′·ied, dirtying dirt′y·ing