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]