Smūt1, n.
n. [Sw. smuts, Dan. smuds, M. H. Ger. smuz, N. H. Ger. schmutz, A-S. smitta; D. smet, a spot or stain, smoddig, smodsig, smodderig, dirty, smodderen, to smut. Cf. SMITT.]
Sense 1. Foul matter, like soot or coal-dust, or the spot or soil which this makes.
Sense 2. (Mining.) Bad, soft coal, containing much earthy matter, found in the immediate locality of faults.
Sense 3. (Bot.) A parasitic fungus (Uredo segetum of most naturalists), which forms on grain, blasting it. Sometimes the whole ear is blasted and converted into smut, as is often the fact with maize.
Sense 4. Obscene language; ribaldry; obscenity.
He does not stand upon decency in conversation, but will talk smut, though a priest and his mother be in the room. Addison.