[syn: demonic, diabolic, diabolical, fiendish, hellish, infernal, satanic, unholy]
The Collaborative International Dictionary of English v.0.48:
Diabolic \Di`a*bol"ic\, Diabolical \Di`a*bol"ic*al\, a. [L.
diabolicus, Gr. ? devilish, slanderous: cf. F. diabolique.
See Devil.]
1. Pertaining to the devil; resembling, or appropriate, or
appropriate to, the devil; befitting hell or satan;
devilish; infernal; impious; as, a diabolic or diabolical
temper or act; the diabolical expression on his face;
fires lit up a diabolic scene. "Diabolic power." --Milton.
"The diabolical institution." --Motley.
Syn: devilish, mephistophelian, mephistophelean.
[1913 Webster]
2. showing a wicked cunning or ingenuity; as, the cold
calculation and diabolic art of some statesmen.
Syn: devilish, mephistophelian, mephistophelean.
[WordNet 1.5]
3. extremely evil or cruel; atrocious; outrageously wicked;
as, diabolical sorcerers under the influence of devils;
diabolical torturers taking pleasure in their craft.
Syn: demonic, fiendish, hellish, infernal, nefarious,
satanic.
[1913 Webster + WordNet 1.5] -- Di`a*bol"ic*al*ly,
adv. -- Di`a*bol"ic*al*ness, n.
WordNet (r) 3.0 (2006):
diabolical
adj 1: 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" [syn: devilish, diabolic, diabolical,
mephistophelian, mephistophelean]
2: 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" [syn: demonic,
diabolic, diabolical, fiendish, hellish, infernal,
satanic, unholy]
Moby Thesaurus II by Grady Ward, 1.0:
61 Moby Thesaurus words for "diabolical":
Draconian, Mephistophelian, Tartarean, animal, anthropophagous,
atrocious, barbaric, barbarous, beastly, bestial, bloodthirsty,
bloody, bloody-minded, brutal, brutalized, brute, brutish,
cannibalistic, cruel, cruel-hearted, cursed, damnable, demoniac,
demoniacal, demonic, demonish, demonlike, devil-like, devilish,
diabolic, execrable, fell, feral, ferocious, fiendish, fiendlike,
fierce, ghoulish, hellborn, hellish, infernal, inhuman, inhumane,
murderous, ogreish, ruthless, sadistic, sanguinary, sanguineous,
satanic, savage, sharkish, slavering, subhuman, truculent,
unchristian, uncivilized, ungodly, unhuman, vicious, wolfish