Definition of Dirty

Adjective: dirty (dirtier,dirtiest) dur-tee

Not clean, or likely to soil with dirt or grime
"dirty unswept pavements"; "a child in dirty overalls"; "dirty slums"; "piles of dirty dishes"; "put his dirty feet on the clean sheet"; "mining is a dirty job"; "Cinderella did the dirty work while her sisters preened themselves";
- soiled, unclean
(of behaviour or especially language) characterized by obscenity or indecency
"dirty words"; "a dirty old man"; "dirty books and movies"; "boys telling dirty jokes"; "has a dirty mouth"
Vile; despicable
"a dirty trick";
- filthy, lousy, cruddy
Spreading pollution or contamination; especially radioactive contamination
"the air near the foundry was always dirty"; "a dirty bomb releases enormous amounts of long-lived radioactive fallout";
- contaminating
Contaminated with infecting organisms
"dirty wounds";
- pestiferous
(of colour) discoloured by impurities; not bright and clear
"dirty"; "a dirty white"; "dirty-green walls"; "dirty-blonde hair";
- dingy, muddied, muddy
(of a manuscript) defaced with changes
"dirty copy";
- foul, marked-up
Obtained illegally or by improper means
"dirty money";
- ill-gotten, misbegotten
Expressing or revealing hostility or dislike
"dirty looks"
Violating accepted standards or rules
"a dirty fighter";
- cheating, foul, unsporting, unsportsmanlike
Unethical or dishonest
"dirty police officers";
- sordid
Unpleasantly stormy
"there's dirty weather in the offing"

Verb: dirty dur-tee

Make soiled, filthy, or dirty
"don't dirty your clothes when you play outside!";
- soil, begrime, grime, colly [archaic], bemire [archaic]

Adverb: dirty dur-tee

In an unfair manner
- unfairly, below the belt
[Brit] Used as an intensifier
"watching the cricket with a dirty big grin";
- very, really, real [N. Amer], rattling, extremely, thoroughly, exceedingly, enormously, tremendously, hugely, staggeringly