diabolical diabolical /ˌdaɪəˈbɑːlɪkəl/

adjective

1. Extremely evil or cruel; expressive of cruelty or befitting hell  ( demonic , diabolic , diabolical , fiendish , hellish , infernal , satanic , unholy )
   extremely evil or cruel; expressive of cruelty or befitting hell
    Something demonic in him--something that could be cruel
   something demonic in him--something that could be cruel
    Fires lit up a diabolic scene
   fires lit up a diabolic scene
    Diabolical sorcerers under the influence of devils
   diabolical sorcerers under the influence of devils
    A fiendish despot
   a fiendish despot
    Hellish torture
   hellish torture
    Infernal instruments of war
   infernal instruments of war
    Satanic cruelty
   satanic cruelty
    Unholy grimaces
   unholy grimaces
   
2. Showing the cunning, ingenuity or wickedness typical of a devil  ( diabolic , diabolical , mephistophelean , devilish , mephistophelian )
   showing the cunning, ingenuity or wickedness typical of a devil
    Devilish schemes
   devilish schemes
    The cold calculation and diabolic art of some statesmen
   the cold calculation and diabolic art of some statesmen
    The diabolical expression on his face
   the diabolical expression on his face
    A mephistophelian glint in his eye
   a mephistophelian glint in his eye