1. 
[syn: demonic, diabolic, diabolical, fiendish, hellish, infernal, satanic, unholy]
2.  of or relating to Satan; 
- Example: "Satanic verses"
The Collaborative International Dictionary of English v.0.48:
Satanic \Sa*tan"ic\, Satanical \Sa*tan"ic*al\, a. [Cf. F.
   satanique, Gr. ?.]
   Of or pertaining to Satan; having the qualities of Satan;
   resembling Satan; extremely malicious or wicked; devilish;
   infernal. "Satanic strength." "Satanic host." --Milton.
   [1913 Webster]
         Detest the slander which, with a Satanic smile, exults
         over the character it has ruined.        --Dr. T.
                                                  Dwight.
   [1913 Webster] -- Sa*tan"ic*al*ly, adv. --
   Sa*tan"ic*al*ness, n.
   [1913 Webster]
WordNet (r) 3.0 (2006):
satanic
    adj 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"
           [syn: demonic, diabolic, diabolical, fiendish,
           hellish, infernal, satanic, unholy]
    2: of or relating to Satan; "Satanic verses"
Moby Thesaurus II by Grady Ward, 1.0:
94 Moby Thesaurus words for "satanic":
   Draconian, Mephistophelian, Tartarean, abhorrent, abominable,
   amoral, animal, anthropophagous, atrocious, barbaric, barbarous,
   beastly, bestial, black, bloodthirsty, bloody, bloody-minded,
   brutal, brutalized, brute, brutish, cannibalistic, corrupt, cruel,
   cruel-hearted, cursed, damnable, dark, demoniac, demoniacal,
   demonic, demonish, demonlike, depraved, despicable, devil-like,
   devilish, diabolic, diabolical, dire, evil, execrable, fell, feral,
   ferocious, fiendish, fiendlike, fierce, ghoulish, godless, heinous,
   hellborn, hellish, hideous, horrendous, horrible, horrid,
   horrifying, immoral, impious, infernal, inhuman, inhumane,
   iniquitous, loathsome, monstrous, murderous, ogreish, perverse,
   perverted, ruthless, sadistic, sanguinary, sanguineous, saturnine,
   savage, serpentine, sharkish, sinister, slavering, subhuman,
   truculent, unchristian, uncivilized, ungodly, unhallowed, unholy,
   unhuman, unspeakable, unutterable, vicious, vile, wicked,
   wolfish