SMUT

I. verb (~ted; ~ting) Etymology: probably alteration of earlier smot to stain, from Middle English smotten; akin to Middle High German ~zen to stain Date: 1587 transitive verb to stain or taint with ~, to affect (a crop or plant) with ~, intransitive verb to become affected by ~, II. noun Date: 1664 matter that soils or blackens, any of various destructive diseases especially of cereal grasses caused by parasitic basidiomycetous fungi (order Ustilaginales) and marked by transformation of plant parts into dark masses of spores, obscene language or matter