The Collaborative International Dictionary of English v.0.48:

Spiritualize \Spir"it*u*al*ize\, v. t. [imp. & p. p.
   Spiritualized; p. pr. & vb. n. Spiritualizing.] [Cf. F.
   spiritualiser.]
   1. To refine intellectiually or morally; to purify from the
      corrupting influence of the world; to give a spiritual
      character or tendency to; as, to spiritualize soul.
      [1913 Webster]

            This seen in the clear air, and the whole
            spiritualized by endless recollections, fills the
            eye and the heart more forcibly than I can find
            words to say.                         --Carlyle.
      [1913 Webster]

   2. To give a spiritual meaning to; to take in a spiritual
      sense; -- opposed to literalize.
      [1913 Webster]

   3. (Old Chem.) To extract spirit from; also, to convert into,
      or impregnate with, spirit.
      [1913 Webster]

WordNet (r) 3.0 (2006):

spiritualize
    v 1: give a spiritual meaning to; read in a spiritual sense
         [syn: spiritualize, spiritualise] [ant: literalise,
         literalize]
    2: elevate or idealize, in allusion to Christ's transfiguration
       [syn: transfigure, glorify, spiritualize]
    3: purify from the corrupting influences of the world; "During
       his stay at the ashram he was spiritualized" [syn:
       spiritualize, spiritualise]

Moby Thesaurus II by Grady Ward, 1.0:

42 Moby Thesaurus words for "spiritualize":
   attenuate, bolt, clarify, clear, decrassify, dematerialize,
   depurate, disembody, disincarnate, distill, edulcorate, elute,
   enervate, essentialize, etherealize, extract, filter, filtrate,
   idealize, immaterialize, insubstantialize, leach, lixiviate,
   percolate, purify, rarefy, rectify, refine, sap, screen, separate,
   sieve, sift, spiritize, strain, sublimate, sublime, subtilize, try,
   unsubstantialize, weaken, winnow