filthiest
Webster's Dictionary (GCIDE)
Filthy \Filth"y\, a. [Compar. Filthier; superl. Filthiest.] Defiled with filth, whether material or moral; nasty; dirty; polluted; foul; impure; obscene. "In the filthy-mantled pool." --Shak. [1913 Webster]
He which is filthy let him be filthy still. --Rev. xxii. 11.
Syn: Nasty; foul; dirty; squalid; unclean; sluttish; gross; vulgar; licentious. See Nasty. [1913 Webster]