"diabolic" in the adjective sense
1. devilish, diabolic, diabolical, mephistophelian, mephistophelean
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"
2. demonic, diabolic, diabolical, fiendish, hellish, infernal, satanic, unholy
extremely evil or cruel expressive of cruelty or befitting hell
"something demonic in him
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