WordNet (r) 3.0 (2006):

nonphysical
    adj 1: lacking substance or reality; incapable of being touched
           or seen; "that intangible thing--the soul" [syn:
           intangible, nonphysical]

Moby Thesaurus II by Grady Ward, 1.0:

35 Moby Thesaurus words for "nonphysical":
   airy, asomatous, astral, bodiless, decarnate, decarnated,
   discarnate, disembodied, ethereal, extramundane, ghostly,
   immaterial, impalpable, imponderable, incorporate, incorporeal,
   insubstantial, intangible, metaphysical, nonmaterial, occult,
   otherworldly, phantom, psychic, shadowy, spiritual, supernatural,
   transmundane, unearthly, unembodied, unextended, unfleshly,
   unphysical, unsubstantial, unworldly