diabolical

Adjective

• extremely evil or cruel; expressive of cruelty or befitting hell
  • something demonic in him--something that could be cruel
    
  • fires lit up a diabolic scene
    
  • diabolical sorcerers under the influence of devils
    
  • a fiendish despot
    
  • hellish torture
    
  • infernal instruments of war
    
  • satanic cruelty
    
  • unholy grimaces
    

• showing the cunning or ingenuity or wickedness typical of a devil
  • devilish schemes
    
  • the cold calculation and diabolic art of some statesmen
    
  • the diabolical expression on his face
    
  • a mephistophelian glint in his eye
    

Related words

• Synonyms: 
  demonic , diabolic , fiendish , hellish , infernal , satanic , unholy , devilish , mephistophelian , mephistophelean