Meaning

noun a black colloidal substance consisting wholly or principally of amorphous carbon and used to make pigments and ink

noun destructive diseases of plants (especially cereal grasses) caused by fungi that produce black powdery masses of spores

noun any fungus of the order Ustilaginales

originFrom Middle English smutten (“to defile, debase”), related to German Schmutz (“filth, dirt, smut”) and schmutzen (“to make dirty, stain”). Doublet of schmutz. Compare also Old English smitta (“smear; blot; mark; stain; pollution”), Old English besmītan (“to besmut; defile; dirty; pollute; contaminate”).

Etymology from Wiktionary, CC BY-SA 3.0