smut
noun
[ smʌt ]
• a small flake of soot or other dirt or a mark left by one.
• "all those black smuts from the engine"
• a fungal disease of cereals in which parts of the ear change to black powder.
• "a few bad crop years with smut and drought and frost"
• obscene or lascivious talk, writing, or pictures.
• "porn, in his view, is far from being harmless smut"
Origin:
late Middle English (in the sense ‘defile, corrupt, make obscene’): related to German schmutzen ; compare with smudge1. The noun dates from the mid 17th century.
