Fig. someone or something that is responsible for something bad or wrong. (Fig. on the villainous role in a drama.) I wonder who told the newspapers about the local scandal. I discovered that Jane was the villain of the piece.We couldn't think who had stolen the meat. The dog next door turned out to be the villain of the piece.
The person to blame for what is bad or wrong, as in I'm afraid the caterer is the villain of the piece-the food wasn't ready for hours. The piece in this term alludes to a play in which the villain is the character whose evildoing is important to the plot. [Mid-1800s]