demoniac
1. [ adjective ] resembling or suggesting possession by a demon
Synonyms: demoniacal
Examples:

"demoniac energy" "a demoniacal fit"

Related terms: agitated
2. [ adjective ] in a murderous frenzy as if possessed by a demon
Synonyms: amok berserk demoniacal possessed amuck
Examples:

"the soldier was completely amuck" "berserk with grief" "a berserk worker smashing windows"

Related terms: insane
3. [ noun ] someone who acts as if possessed by a demon
Related terms: monster
Similar spelling:   demoniacal
  demonic
  denounce
  demonize
  demonism
  demonise
  Denning
  Demming
  deinonychus