Definition

1. Adjective:
   • Extremely evil, cruel, or wicked; characteristic of or befitting a devil or hell: Describes something or someone that is profoundly, shockingly evil, often with a sense of supernatural malevolence.
   • Showing fiendish cunning, ingenuity, or wickedness: Describes cleverness or planning that is used for profoundly evil purposes.

Usage Examples

• Describing an action or nature:
  • The villain's plan was a diabolic scheme to control the world.
  • The dictator was known for his diabolic cruelty towards political prisoners.
• Describing an appearance or atmosphere:
  • The dark castle had a diabolic aura that frightened the villagers.
  • He smiled with a diabolic grin, revealing his true intentions.

Advanced Usage

• "Diabolic" vs. "Diabolical": Both forms are adjectives and are generally interchangeable in modern usage, meaning "extremely evil." "Diabolical" is slightly more common.
  • The evidence pointed to a diabolical plot.
• In a figurative or exaggerated sense: Sometimes used to describe something that is extremely difficult, annoying, or complex, though this is informal.
  • The exam contained some diabolically hard questions. (Here, "diabolically" is the adverb form).

Variants and Related Words

• Diabolical (adj): The more common variant, identical in meaning to "diabolic."
• Diabolically (adv): In an extremely evil or fiendishly clever manner.
  • The trap was diabolically clever.
• Diabolism (n): Worship of or belief in devils; sorcery.
• Diabolist (n): A person who practices diabolism.

Synonyms

• Fiendish: Extremely cruel or unpleasant; characteristic of a fiend.
• Demonic: Of, like, or characteristic of a demon or evil spirit.
• Satanic: Of or characteristic of Satan; supremely evil or wicked.
• Infernal: Of or relating to hell; hellish (often used for emphasis).
• Mephistophelian: Cunning, fiendish, and cynical (from the literary character Mephistopheles).
• Wicked: Evil or morally wrong.

Related Phrases and Idioms

• A diabolic/diabolical plan: An extremely evil and clever plan.
  • The detective uncovered the criminal's diabolical plan.
• Diabolic/diabolical laughter: Laughter that sounds evil or menacing.
  • His diabolic laughter echoed through the hall.

Adjective

1. 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
2. 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