filthn.[OE. filthe, fule, AS. fl, fr. fl foul; akin to OHG. flida. See Foul, and cf. File.]1. Foul matter; anything that soils or defiles; dirt; nastiness.()2. Anything that sullies or defiles the moral character; corruption; pollution.()To purify the soul from the dross and filth of sensual delights. (Tillotson.)Filth disease (Med.), a disease supposed to be due to pollution of the soil or water.()