n. 1 repugnant or extreme dirt. 2 obscenity. [Old English: related to Foul.] filthy adj. (ier, lest) 1 extremely or disgustingly dirty. 2 obscene. 3 colloq. (of weather) very unpleasant. adv. 1 filthily (filthy dirty). 2 colloq. extremely (filthy rich). filthily ado. filthiness n.
