adjective, filth·i·er, filth·i·est.
- foul with, characterized by, or having the nature of filth; disgustingly or completely dirty.
- vile; vulgar; obscene: filthy language.
- contemptibly offensive, vile, or objectionable: to treat one’s friends in a filthy manner.
- (of money) abundantly supplied (often followed by with): They’re filthy with money.
verb (used with object), filth·ied, filth·y·ing.
- to make filthy; foul.
- filthy rich, outrageously wealthy; very rich.
adjective filthier or filthiest
- characterized by or full of filth; very dirty or obscene
- offensive or viciousthat was a filthy trick to play
- informal, mainly British extremely unpleasantfilthy weather
adverb
- extremely; disgustinglyfilthy rich
late 12c., fulthe, “corrupt, sinful,” from filth + -y (2). Meaning “physically unclean” is from late 14c. Meaning “morally dirty, obscene” is from 1530s.
In early use often hardly more emphatic than the mod. dirty; it is now a violent expression of disgust, seldom employed in polite colloquial speech. [OED]
Related: Filthiness.