1. 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

Similar word(s): evil, devilish, diabolic, mephistophelean, mephistophelian

2. extremely evil or cruel; expressive of cruelty or befitting hell

- fires lit up a diabolic scene

- diabolical sorcerers under the influence of devils

Similar word(s): evil, demonic, diabolic, fiendish, hellish, infernal, satanic, unholy