The Collaborative International Dictionary of English v.0.48:

Ghostly \Ghost"ly\, a. [OE. gastlich, gostlich, AS. g[=a]stlic.
   See Ghost.]
   1. Relating to the soul; not carnal or secular; spiritual;
      as, a ghostly confessor.
      [1913 Webster]

            Save and defend us from our ghostly enemies. --Book
                                                  of Common
                                                  Prayer [Ch. of
                                                  Eng. ]
      [1913 Webster]

            One of the gostly children of St. Jerome. --Jer.
                                                  Taylor.
      [1913 Webster]

   2. Of or pertaining to apparitions. --Akenside.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ghostly \Ghost"ly\, adv.
   Spiritually; mystically. --Chaucer.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ghostly
    adj 1: resembling or characteristic of a phantom; "a ghostly
           face at the window"; "a phantasmal presence in the room";
           "spectral emanations"; "spiritual tappings at a seance"
           [syn: apparitional, ghostlike, ghostly,
           phantasmal, spectral, spiritual]

Moby Thesaurus II by Grady Ward, 1.0:

75 Moby Thesaurus words for "ghostly":
   airy, asomatous, astral, blue, bodiless, cadaverous, corpselike,
   creepy, deadly, deathlike, deathly, deathly pale, decarnate,
   decarnated, discarnate, disembodied, ectoplasmic, eerie, ethereal,
   etheric, extramundane, ghastly, ghostish, ghostlike, ghosty,
   grisly, gruesome, haggard, immaterial, impalpable, imponderable,
   incorporate, incorporeal, insubstantial, intangible, livid, lurid,
   macabre, mortuary, nonmaterial, nonphysical, occult, otherworldly,
   pale, phantasmal, phantasmic, phantom, phantomic, phantomlike,
   preternatural, psychic, scary, shadowy, sinister, specterlike,
   spectral, spiritual, spooky, strange, supernatural, transmundane,
   uncanny, unearthly, unembodied, unextended, unfleshly, unnatural,
   unphysical, unreal, unsubstantial, unworldly, wan, weird,
   wraithlike, wraithy