The Collaborative International Dictionary of English v.0.48:

Supernaturalism \Su`per*nat"u*ral*ism\, n.
   1. The quality or state of being supernatural;
      supernaturalness.
      [1913 Webster]

   2. (Theol.) The doctrine of a divine and supernatural agency
      in the production of the miracles and revelations recorded
      in the Bible, and in the grace which renews and sanctifies
      men, -- in opposition to the doctrine which denies the
      agency of any other than physical or natural causes in the
      case. [Written also supranaturalism.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

supernaturalism
    n 1: a belief in forces beyond ordinary human understanding
    2: the quality of being attributed to power that seems to
       violate or go beyond natural forces [syn: supernaturalism,
       supernaturalness]

Moby Thesaurus II by Grady Ward, 1.0:

48 Moby Thesaurus words for "supernaturalism":
   bodilessness, eeriness, elfdom, faerie, ghostliness, immateriality,
   immaterialness, impalpability, imponderability, incorporeality,
   incorporeity, inextension, intangibility, miraculousness,
   mysteriousness, mystery, nonexteriority, numinousness,
   occult phenomena, occultism, otherworldliness, preternaturalism,
   psychical research, psychicism, psychics, psychism, shadowiness,
   spirit world, spirituality, spirituousness, superhumanity,
   supernaturality, supernaturalness, supernature, supernormalness,
   superphysicalness, supersensibleness, supranaturalism, supranature,
   the occult, the supernatural, the supersensible, transcendentalism,
   unearthliness, unsubstantiality, unsubstantialness, unworldliness,
   witchery