spectral

spectral
    adj 1: of or relating to a spectrum; "spectral colors";
           "spectral analysis"
    2: 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}]
    

Spectral \Spec"tral\, a.
   1. Of or pertaining to a specter; ghosty.
      [1913 Webster]

            He that feels timid at the spectral form of evil is
            not the man to spread light.          --F. W.
                                                  Robertson.
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   2. (Opt.) Of or pertaining to the spectrum; made by the
      spectrum; as, spectral colors; spectral analysis.
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   {Spectral lemur}. (Zool.) See {Tarsius}.
      [1913 Webster]
    

118 Moby Thesaurus words for "spectral":
      Barmecidal, Barmecide, airy, apparent, apparitional, astral,
      autistic, bicolor, bicolored, cadaverous, chimeric, chromatic,
      cold, colorful, colorific, coloring, colory, cool, corpselike,
      crazy, daedal, deathlike, deceptive, delusional, delusionary,
      delusive, delusory, dereistic, dichromatic, disembodied,
      divers-colored, dreamlike, dreamy, ectoplasmic, eerie, erroneous,
      ethereal, etheric, fallacious, false, fantastic, ghostish,
      ghostlike, ghostly, ghosty, glowing, harlequin, harmonious,
      illusional, illusionary, illusive, illusory, imaginary,
      incorporeal, kaleidoscopic, many-colored, matching, medley,
      misleading, monochromatic, monochrome, monochromic, motley,
      multicolor, multicolored, multicolorous, ostensible, parti-color,
      parti-colored, phantasmagoric, phantasmal, phantasmic, phantom,
      phantomic, phantomlike, pigmentary, polychromatic, polychrome,
      polychromic, prismal, prismatic, psychic, rainbow, seeming,
      self-deceptive, self-deluding, shadowy, shot, shot through,
      specious, specterlike, spiritual, spooky, supernatural,
      supposititious, thunder and lightning, tinctorial, tingent, toning,
      trichromatic, trichromic, tricolor, tricolored, two-tone, unactual,
      unearthly, unfounded, unreal, unsubstantial, varicolored,
      variegated, versicolor, versicolored, visionary, warm, weird,
      wraithlike, wraithy