Diabolic; Diabolical

Part of speech: adjective (a.)

Pertaining to the devil; resembling, or appropriate, or appropriate to, the devil; devilish; infernal; impious; atrocious; nefarious; outrageously wicked; as, a diabolic or diabolical temper or act. "Diabolic power." Milton. "The diabolical institution." Motley. -- Di`a*bol"ic*al*ly, adv. -- Di`a*bol"ic*al*ness, n.