eldritch

from WordNet (r) 3.0 (2006)

eldritch
    adj 1: suggesting the operation of supernatural influences; "an
           eldritch screech"; "the three weird sisters";
           "stumps...had uncanny shapes as of monstrous creatures"-
           John Galsworthy; "an unearthly light"; "he could hear the
           unearthly scream of some curlew piercing the din"- Henry
           Kingsley [syn: {eldritch}, {weird}, {uncanny},
           {unearthly}]

from The Collaborative International Dictionary of English v.0.48

Eldritch \El"dritch\, a.
   Hideous; ghastly; as, an eldritch shriek or laugh. [Local,
   Eng.]
   [1913 Webster]