n. 1 a person guilty or capable of great wickedness. 2 colloq. usu. joc. a rascal or rogue. 3 (also villain of the piece) (in a play etc.) a character whose evil actions or motives are important in the plot. 4 Brit. colloq. a professional criminal. 5 archaic a rustic; a boor.
[ ME f. OF vilein, vilain ult. f. L villa: see VILLA ]