from
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.