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.
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   2. Of or pertaining to apparitions. --Akenside.
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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]