adjective

covered or marked with an unclean substance.

a tray of dirty cups and saucers

soiled,grimy,grubby,filthy,mucky,stained,unwashed,greasy,smeared,smeary,spotted,smudged,cloudy,muddy,dusty,sooty,unclean,sullied,impure,tarnished,polluted,contaminated,defiled,foul,unhygienic,insanitary,unsanitary,cruddy,yucky,icky,manky,gungy,grotty,bogging,befouled,besmirched,begrimed,feculent

adverb

used for emphasis.

a dirty great slab of stone

verb

make dirty.

she didn’t like him dirtying her nice clean towels

soil,stain,muddy,blacken,mess up,spoil,tarnish,taint,make dirty,mark,spatter,bespatter,smudge,smear,daub,spot,splash,splatter,sully,pollute,foul,defile,befoul,besmirch,begrime