n. A spot made with soot, coal, or the like; also, the fouling matter itself.n. Obscene or filthy language.n. A fungous disease of plants, affecting especially the cereal plants, to many of which it is exceedingly destructive.n. Earthy, worthless coal, such as is often found at the outcrop of a seam. In Pennsylvania also called black-dirt, blossom, and crop.To stain or mark with smut; blacken with coal, soot, or other dirty substance.To affect with the disease called smut; mildew.Figuratively, to tarnish; defile; make impure; blacken.To make obscene.To gather smut; be converted into smut.To give off smut; crock.In leather manufacturing, to go over (the blacked side of a hide or skin) with a woolen cloth to remove dirt and improve the appearance of the blacking.