The Collaborative International Dictionary of English v.0.48:

Disenchant \Dis`en*chant"\, v. t. [imp. & p. p. Disenchanted;
   p. pr. & vb. n. Disenchanting.] [Pref. dis- + enchant: cf.
   F. d['e]senchanter.]
   1. To free from enchantment; to deliver from the power of
      charms or spells.
      [1913 Webster]

            Haste to thy work; a noble stroke or two
            Ends all the charms, and disenchants the grove.
                                                  --Dryden.
      [1913 Webster]

   2. to free (a person) from fascination or delusion; to
      destroy the false hopes or overoptimistic expectations of
      (a person); to disillusion; -- used with people or events
      as the agent (subject); as, the candidate was disenchanted
      by the low turnout at the rally.
      [PJC]

WordNet (r) 3.0 (2006):

disenchant
    v 1: free from enchantment [syn: disenchant, disillusion]
         [ant: delight, enchant, enrapture, enthral,
         enthrall, ravish, transport]

Moby Thesaurus II by Grady Ward, 1.0:

25 Moby Thesaurus words for "disenchant":
   awaken, break the spell, burst the bubble, correct, debunk,
   disabuse, disappoint, disillude, disillusion, disillusionize,
   enlighten, expose, let down easy, let in on, prick the bubble,
   put straight, set right, set straight, show up, tell the truth,
   unblindfold, uncharm, undeceive, unspell, wake up