1) Characterized by obscenity 2) Despicable 3) Dirt-covered 4) Dirty 5) Disgustingly dirty 6) Fetid 7) Foul 8) Foul-mouthed 9) Kind of rich 10) Like the police, being rude 11) Nasty 12) Neglected 13) Obscene 14) Soiled 15) Unclean 16) Very dirty 17) Vile 18) Word before rich Found on https://www.crosswordclues.com/clue/filthy
Filth'y adjective [ Compar. Filthier ; superl. Filthiest .] Defiled with filth, whether material or moral; nasty; dirty; polluted; foul; impure; obscene. 'In the filthy -mantled pool.' Shak. « He which is filthy... Found on http://www.encyclo.co.uk/webster/F/29
fouladjective disgustingly dirty; filled or smeared with offensive matter; `as filthy as a pigsty`; `a foul pond`; `a nasty pigsty of a room` Found on https://www.encyclo.co.uk/local/20974