The Collaborative International Dictionary of English v.0.48:

Gratify \Grat"i*fy\, v. t. [imp. & p. p. Gratified; p. pr. &
   vb. n. Gratifying.] [F. gratifier, L. gratificari; gratus
   pleasing + -ficare (in comp.) to make. See -fy.]
   1. To please; to give pleasure to; to satisfy; to soothe; to
      indulge; as, to gratify the taste, the appetite, the
      senses, the desires, the mind, etc.
      [1913 Webster]

            For who would die to gratify a foe?   --Dryden.
      [1913 Webster]

   2. To requite; to recompense. [Obs.]
      [1913 Webster]

            It remains . . .
            To gratify his noble service.         --Shak.

   Syn: To indulge; humor please; delight; requite; recompense.

   Usage: To Gratify, Indulge, Humor. Gratify, is the
          generic term, and has reference simply to the pleasure
          communicated. To indulge a person implies that we
          concede something to his wishes or his weaknesses
          which he could not claim, and which had better,
          perhaps, be spared. To humor is to adapt ourselves to
          the varying moods, and, perhaps, caprices, of others.
          We gratify a child by showing him the sights of a
          large city; we indulge him in some extra expense on
          such an occasion; we humor him when he is tired and
          exacting.
          [1913 Webster]

WordNet (r) 3.0 (2006):

gratify
    v 1: make happy or satisfied [syn: satisfy, gratify] [ant:
         dissatisfy]
    2: yield (to); give satisfaction to [syn: gratify, pander,
       indulge]

Moby Thesaurus II by Grady Ward, 1.0:

56 Moby Thesaurus words for "gratify":
   achieve inner harmony, allay, appease, assuage, baby, board, bread,
   cater to, cheer, coddle, compensate, content, cosset, delectate,
   delight, dine, do proud, elate, favor, feast, feed, flush, fodder,
   forage, give way to, gladden, grass, graze, happify, humor,
   indulge, make proud, meat, mess, mollycoddle, oblige, pamper,
   pasture, please, pleasure, provision, put at ease, quench,
   recompense, regale, requite, reward, sate, satiate, satisfy,
   set at ease, slake, spoil, sustain, wine and dine, yield to