The Collaborative International Dictionary of English v.0.48:

Blanch \Blanch\ (bl[.a]nch), v. t. [imp. & p. p. Blanched
   (bl[.a]ncht); p. pr. & vb. n. Blanching.] [OE. blanchen,
   blaunchen, F. blanchir, fr. blanc white. See Blank, a.]
   [1913 Webster]
   1. To take the color out of, and make white; to bleach; as,
      to blanch linen; age has blanched his hair.
      [1913 Webster]

   2. (Gardening) To bleach by excluding the light, as the
      stalks or leaves of plants, by earthing them up or tying
      them together.
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   3. (Confectionery & Cookery)
      (a) To make white by removing the skin of, as by scalding;
          as, to blanch almonds.
      (b) To whiten, as the surface of meat, by plunging into
          boiling water and afterwards into cold, so as to
          harden the surface and retain the juices.
          [1913 Webster]

   4. To give a white luster to (silver, before stamping, in the
      process of coining.).
      [1913 Webster]

   5. To cover (sheet iron) with a coating of tin.
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   6. Fig.: To whiten; to give a favorable appearance to; to
      whitewash; to palliate.
      [1913 Webster]

            Blanch over the blackest and most absurd things.
                                                  --Tillotson.
      [1913 Webster]

   Syn: To Blanch, Whiten.

   Usage: To whiten is the generic term, denoting, to render
          white; as, to whiten the walls of a room. Usually
          (though not of necessity) this is supposed to be done
          by placing some white coloring matter in or upon the
          surface of the object in question. To blanch is to
          whiten by the removal of coloring matter; as, to
          blanch linen. So the cheek is blanched by fear, i. e.,
          by the withdrawal of the blood, which leaves it white.
          [1913 Webster]

WordNet (r) 3.0 (2006):

blanched
    adj 1: anemic looking from illness or emotion; "a face turned
           ashen"; "the invalid's blanched cheeks"; "tried to speak
           with bloodless lips"; "a face livid with shock";
           "lips...livid with the hue of death"- Mary W. Shelley;
           "lips white with terror"; "a face white with rage" [syn:
           ashen, blanched, bloodless, livid, white]
    2: (especially of plants) developed without chlorophyll by being
       deprived of light; "etiolated celery" [syn: etiolate,
       etiolated, blanched]

Moby Thesaurus II by Grady Ward, 1.0:

59 Moby Thesaurus words for "blanched":
   aghast, appalled, ashen, ashy, astounded, awed, awestricken,
   awestruck, bleached, bleached white, colorless, cowed, deadly pale,
   decolored, decolorized, doughy, drained, drained of color, eroded,
   faded, frozen, gray with fear, horrified, horror-struck,
   intimidated, lightened, livid, pale as death, pallid, paralyzed,
   petrified, scared stiff, scared to death, stunned, stupefied,
   terrified, terror-crazed, terror-haunted, terror-ridden,
   terror-riven, terror-shaken, terror-smitten, terror-struck,
   terror-troubled, undone, unmanned, unnerved, unstrung, wan,
   washed-out, waxen, weather-battered, weather-beaten,
   weather-bitten, weather-eaten, weather-wasted, weathered,
   weatherworn, whitened