showing the cunning or ingenuity or wickedness typical of a devil;
"the cold calculation and diabolic art of some statesmen"
"the diabolical expression on his face"
"a mephistophelian glint in his eye"
- Although he lived with his mother and two sisters throughout his adult life, when he died there were 14 outstanding paternity suits against him, which might explain his Mephistophelean smile.
- a mephistophelean plan, trick, etc
- mephistophelean cunning