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):

indulging
    n 1: the act of indulging or gratifying a desire [syn:
         indulgence, indulging, pampering, humoring]