diabolical

Adjective Satellite

• showing the cunning or ingenuity or wickedness typical of a devil
  • "the diabolical expression on his face"
• extremely evil or cruel; expressive of cruelty or befitting hell
  • "diabolical sorcerers under the influence of devils"

Adj

• Of or concerning the devil: devilish, satanic.
• Extremely wicked or cruel.
• (Devilishly) cunning or devious.
• Crazy, wild (sometimes especially due to being unexpected or surprising).

Examples

• a diabolical plan

Synonyms

demonic, devilish, diabolic, fiendish, hellish, infernal, mephistophelean, mephistophelian, satanic, unholy