filthy

Filthy is an English adjective used to describe something that is very dirty or unsanitary, such as filthy clothes, filthy streets, or a filthy kitchen. It also appears in figurative senses to denote moral impurity, corruption, or obscene content, as in filthy tricks, filthy language, or a filthy joke. The term can function as part of idiomatic phrases that intensify the quality described, for example “filthy rich” or “filthy language.”

Etymology and development: Filthy derives from Old English fylþ (filth) and related Proto-Germanic roots tied to dirt and uncleanliness. The adjective existed in Middle English with senses close to the literal meaning, and over time its figurative uses broadened to include moral and ethical deficiency, as well as disreputable or indecent behavior. The phrase filthy lucre, meaning money obtained through dishonest means, reflects the longstanding moral association of the word.

Usage and nuance: Filthy commonly appears in standard and colloquial contexts, with stronger connotations in informal speech. It can describe physical uncleanliness, but is also employed to emphasize vulgarity, corruption, or excess—for example, “filthy jokes” or “filthy allegations.” While widely understood, its blunt or provocative tone may be inappropriate in formal writing or polite conversation. The term often coexists with milder synonyms such as dirty, unclean, obscene, or sordid, depending on the intended emphasis.

See also: Filth; Filthiness; Filthy lucre; Obscenity in language.