- diabolic⇄adv. diabolically.
- diabolic⇄diabolic, adjective.
1. like the Devil; very cruel or wicked; devilish; fiendish.
Ex. The police discovered a diabolic plot to poison the city's drinking water.
(SYN) satanic.
2. of or having to do with the Devil or devils.diabolic⇄noun diabolicalness.