smut

Concise Oxford English Dictionary © 2008 Oxford University Press:
smut/smʌt/

▶noun

• 1 a small flake of soot or dirt.

• 2 a fungal disease of cereals in which parts of the ear change to black powder.

• 3 indecent or obscene talk, writing, or pictures.

▶verb (smuts, smutting, smutted)

• 1 mark with smuts.

• 2 infect with smut.

– derivatives
smuttily adverb,
smuttiness noun,
smutty adjective (smuttier, smuttiest).

– origin ME (in the sense ‘defile, make obscene’).