Source : Webster's Revised Unabridged Dictionary (1913)

Ghastly \Ghast"ly\, a. [Compar. {Ghastlier}; superl.
   {Ghastliest}.] [OE. gastlich, gastli, fearful, causing fear,
   fr. gasten to terrify, AS. g[ae]stan. Cf. {Aghast}, {Gast},
   {Gaze}, {Ghostly}.]
   1. Like a ghost in appearance; deathlike; pale; pallid;
      dismal.

            Each turned his face with a ghastly pang.
                                                  --Coleridge.

            His face was so ghastly that it could scarcely be
            recognized.                           --Macaulay.

   2. Horrible; shocking; dreadful; hideous.

            Mangled with ghastly wounds through plate and mail.
                                                  --Milton.

Source : WordNet®

ghastliest
     See {ghastly}

ghastly
     adj 1: shockingly repellent; inspiring horror; "ghastly wounds";
            "the grim aftermath of the bombing"; "the grim task of
            burying the victims"; "a grisly murder"; "gruesome
            evidence of human sacrifice"; "macabre tales of war
            and plague in the Middle ages"; "macabre tortures
            conceived by madmen" [syn: {grim}, {grisly}, {gruesome},
             {macabre}]
     2: gruesomely indicative of death or the dead; "a charnel smell
        came from the chest filled with dead men's bones";
        "ghastly shrieks"; "the sepulchral darkness of the
        catacombs" [syn: {charnel}, {sepulchral}]
     [also: {ghastliest}, {ghastlier}]