Chapter Smoke-dry to Smut of S by Webster's Dictionary (1913 Edition)

2. (Mining) Bad, soft coal, containing much earthy matter, found in the immediate locality of faults.

3. (Bot.) An affection of cereal grains producing a swelling which is at length resolved into a powdery sooty mass. It is caused by parasitic fungi of the genus Ustilago. Ustilago segetum, or U. Carbo, is the commonest kind; that of Indian corn is Ustilago maydis.

4. Obscene language; ribaldry; obscenity.

He does not stand upon decency . . . but will talk smut, though a priest and his mother be in the room.

Addison.

Smut mill, a machine for cleansing grain from smut.

Smut
(Smut) v. t. [imp. & p. p. Smutted; p. pr. & vb. n. Smutting.]

1. To stain or mark with smut; to blacken with coal, soot, or other dirty substance.

2. To taint with mildew, as grain. Bacon.

3. To blacken; to sully or taint; to tarnish.

4. To clear of smut; as, to smut grain for the mill.

Smut
(Smut), v. i.

1. To gather smut; to be converted into smut; to become smutted. Mortimer.

2. To give off smut; to crock.