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 (dĭ-mō′nē-ăk′) also de·mo·ni·a·cal (dē′mə-nī′ə-kəl)
1. Possessed, produced, or influenced by a demon: demoniac creatures.
2. Of, resembling, or suggestive of a devil; fiendish: demoniac energy; a demoniacal fit.
One who is or seems to be possessed by a demon.

[Middle English demoniak, from Late Latin daemoniacus, from Greek *daimoniakos, from daimonios, of a spirit, from daimōn, divine power; see demon.]

de′mo·ni′a·cal·ly adv.


1. of, like, or suggestive of a demon; demonic
2. suggesting inner possession or inspiration: the demoniac fire of genius.
3. frantic; frenzied; feverish: demoniac activity.
(Theology) a person possessed by an evil spirit or demon
ˌdemoˈniacally adv


(dɪˈmoʊ niˌæk, ˌdi məˈnaɪ æk)

adj. Also, de•mo•ni•a•cal (ˌdi məˈnaɪ ə kəl)
1. of, pertaining to, or like a demon; demonic.
2. possessed by or as if by an evil spirit; raging; frantic.
[1350–1400; Middle English < Late Latin daemoniacus < Greek daimoniakós]
de`mo•ni′a•cal•ly, adv.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.demoniac - someone who acts as if possessed by a demon
fiend, ogre, demon, monster, devil - a cruel wicked and inhuman person
Adj.1.demoniac - frenzied as if possessed by a demondemoniac - frenzied as if possessed by a demon; "the soldier was completely amuck"; "berserk with grief"; "a berserk worker smashing windows"
insane - afflicted with or characteristic of mental derangement; "was declared insane"; "insane laughter"


A. ADJ = demoniacal
B. Ndemoníaco/a m/f, demoniaco/a m/f


nBesessene(r) mf


[dɪˈməʊnɪæk] demoniacal [ˌdiːməʊˈnaɪəkl] adjdemoniaco/a, diabolico/a
References in classic literature ?
They think me mad --Starbuck does; but I'm demoniac, I am madness maddened
And now that at the proper time and place, after so long and wide a preliminary cruise, Ahab, --all other whaling waters swept --seemed to have chased his foe into an ocean-fold, to slay him the more securely there; now, that he found himself hard by the very latitude and longitude where his tormenting wound had been inflicted; now that a vessel had been spoken which on the very day preceding had actually encountered Moby Dick; --and now that all his successive meetings with various ships contrastingly concurred to show the demoniac indifference with which the white whale tore his hunters, whether sinning or sinned against; now it was that there lurked a something in the old man's eyes, which it was hardly sufferable for feeble souls to see.
That pale, loving mother,--her dying prayers, her forgiving love,--wrought in that demoniac heart of sin only as a damning sentence, bringing with it a fearful looking for of judgment and fiery indignation.
This was a demoniac laugh--low, suppressed, and deep--uttered, as it seemed, at the very keyhole of my chamber door.
When the Count saw my face, his eyes blazed with a sort of demoniac fury, and he suddenly made a grab at my throat.
and a frightful, demoniac laugh finished the sentence, which was lost in a hoarse rattle.
By this time the Indian was far out of reach, and had rejoined his men, and the whole dare-devil band, with the captured horses, scuttled off along the defiles, their red flag flaunting overhead, and the rocks echoing to their whoops and yells, and demoniac laughter.
Thus sped the demoniac on his course, until, quivering among the trees, he saw a red light before him, as when the felled trunks and branches of a clearing have been set on fire, and throw up their lurid blaze against the sky, at the hour of midnight.
With such strange compelling qualities, is it any wonder that there is abroad an idea that in the race there is some demoniac possession, which tends to a more definite belief that certain individuals have in the past sold themselves to the Devil?
Whether that Hungarian fugitive would ever be caught appeared to Horne Fisher to be highly doubtful; nor can it be pretended that he displayed any very demoniac detective energy in the matter as he leaned back in the boat cushions, smoking, and watching the swaying reeds slide past.
She hath a demoniac goat with horns of the devil, which reads, which writes, which knows mathematics like Picatrix, and which would suffice to hang all Bohemia.
Rolling over and over upon the turf the two battled with demoniac fury, until the colossal cat, by doubling his hind paws far up beneath his belly sank his talons deep into Taglat's chest, then, ripping downward with all his strength, Numa accomplished his design, and the disemboweled anthropoid, with a last spasmodic struggle, relaxed in limp and bloody dissolution beneath his titanic adversary.