The Collaborative International Dictionary of English v.0.48:

Idealize \I*de"al*ize\, v. t. [imp. & p. p. Idealized; p. pr.
   & vb. n. Idealizing.]
   1. To make ideal; to consider as ideal; to give an ideal form
      or value to; to attribute ideal characteristics and
      excellences to; as, to idealize real life. [WordNet sense
      1]
      [1913 Webster]

   2. (Fine Arts) To treat in an ideal manner. See
      Idealization, 2.
      [1913 Webster]

   3. to form ideals. [WordNet sense 2]
      [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Idealize \I*de"al*ize\, v. i. [Cf. F. id['e]aliser.]
   To form ideals.
   [1913 Webster]

WordNet (r) 3.0 (2006):

idealize
    v 1: consider or render as ideal; "She idealized her husband
         after his death" [syn: idealize, idealise]
    2: form ideals; "Man has always idealized" [syn: idealize,
       idealise]

Moby Thesaurus II by Grady Ward, 1.0:

34 Moby Thesaurus words for "idealize":
   apotheosize, deify, dematerialize, disembody, disincarnate,
   elevate, ennoble, etherealize, exaggerate, exalt, glorify,
   immaterialize, overappraise, overassess, overcalculate, overcount,
   overesteem, overestimate, overmeasure, overprize, overrate,
   overreact to, overreckon, overstate, overvalue, quixotize,
   rhapsodize, romance, romanticize, spiritize, spiritualize,
   unsubstantialize, utopianize, worship