The Collaborative International Dictionary of English v.0.48:

Indulge \In*dulge"\, v. i.
   To indulge one's self; to gratify one's tastes or desires;
   esp., to give one's self up (to); to practice a forbidden or
   questionable act without restraint; -- followed by in, but
   formerly, also, by to. "Willing to indulge in easy vices."
   --Johnson.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Indulge \In*dulge"\, v. t. [imp. & p. p. Indulged; p. pr. &
   vb. n. Indulging.] [L. indulgere to be kind or tender to
   one; cf. OIr. dilgud, equiv. to L. remissio, OIr. dligeth,
   equiv. to L. lex, Goth. dulgs debt.]
   [1913 Webster]
   1. To be complacent toward; to give way to; not to oppose or
      restrain;
      (a) when said of a habit, desire, etc.: to give free
          course to; to give one's self up to; as, to indulge
          sloth, pride, selfishness, or inclinations;
      (b) when said of a person: to yield to the desire of; to
          gratify by compliance; to humor; to withhold restraint
          from; as, to indulge children in their caprices or
          willfulness; to indulge one's self with a rest or in
          pleasure.
          [1913 Webster]

                Hope in another life implies that we indulge
                ourselves in the gratifications of this very
                sparingly.                        --Atterbury.
          [1913 Webster]

   2. To grant as by favor; to bestow in concession, or in
      compliance with a wish or request.
      [1913 Webster]

            Persuading us that something must be indulged to
            public manners.                       --Jer. Taylor.
      [1913 Webster]

            Yet, yet a moment, one dim ray of light
            Indulge, dread Chaos, and eternal Night! --Pope.
      [1913 Webster]

   Note: It is remarked by Johnson, that if the matter of
         indulgence is a single thing, it has with before it; if
         it is a habit, it has in; as, he indulged himself with
         a glass of wine or a new book; he indulges himself in
         idleness or intemperance. See Gratify.
         [1913 Webster]

WordNet (r) 3.0 (2006):

indulge
    v 1: give free rein to; "The writer indulged in metaphorical
         language"
    2: yield (to); give satisfaction to [syn: gratify, pander,
       indulge]
    3: enjoy to excess; "She indulges in ice cream" [syn: indulge,
       luxuriate]
    4: treat with excessive indulgence; "grandparents often pamper
       the children"; "Let's not mollycoddle our students!" [syn:
       pamper, featherbed, cosset, cocker, baby, coddle,
       mollycoddle, spoil, indulge]

Moby Thesaurus II by Grady Ward, 1.0:

105 Moby Thesaurus words for "indulge":
   accommodate with, adore, afford, appreciate, baby, bask, bask in,
   bay, be pleased with, bear, bear with, benignancy, benignity,
   blink at, brook, cater to, clemency, cocker, coddle, comply with,
   condone, connive at, cosset, countenance, courtesy, delight,
   delight in, derive pleasure from, devour, dispensation, eat up,
   endure, enjoy, favor, favor with, feast on, freak out on, furnish,
   gentleness, get high on, give way to, gloat over, gratify,
   groove on, have, heap upon, hear of, humor, indulge in,
   indulge with, indulgence, kindliness, kindness, lavish upon,
   lenience, leniency, like, live high, live well, love, luxuriate,
   luxuriate in, mercifulness, mildness, minister to, mollycoddle,
   much, oblige, overlook, pamper, pander to, please, pour on,
   provide, provide for, put up with, regale, rejoice in, relish,
   revel, revel in, riot in, roll, roll in, rollick, satisfy, savor,
   shower down upon, smack the lips, spoil, stand for, stomach,
   succumb to, suffer, supply, swim in, take pleasure in, tolerance,
   tolerate, toleration, treat to, wallow in, welter, wink at,
   yield to