Source : Webster's Revised Unabridged Dictionary (1913)

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.

Source : WordNet®

smut
     n 1: a black colloidal substance consisting wholly or principally
          of amorphous carbon and used to make pigments and ink
          [syn: {carbon black}, {lampblack}, {soot}]
     2: destructive diseases of plants (especially cereal grasses)
        caused by fungi that produce black powdery masses of
        spores
     3: any fungus of the order Ustilaginales [syn: {smut fungus}]
     4: creative activity (writing or pictures or films etc.) of no
        literary or artistic value other than to stimulate sexual
        desire [syn: {pornography}, {porno}, {porn}, {erotica}]
     [also: {smutting}, {smutted}]

smut
     v 1: make obscene; "This line in the play smuts the entire act"
     2: stain with a dirty substance, such as soot
     3: become affected with smut; "the corn smutted and could not
        be eaten"
     4: affect with smut or mildew, as of a crop such as corn
     [also: {smutting}, {smutted}]

smutting
     See {smut}