The Collaborative International Dictionary of English v.0.48:

Condescend \Con`de*scend"\, v. i. [imp. & p. p. Condescended;
   p. pr. & vb. n. Condescending.] [F. condescendre, LL.
   condescendere, fr. L. con- + descendere. See Descend.]
   1. To stoop or descend; to let one's self down; to submit; to
      waive the privilege of rank or dignity; to accommodate
      one's self to an inferior. "Condescend to men of low
      estate." --Rom. xii. 16.
      [1913 Webster]

            Can they think me so broken, so debased
            With corporal servitude, that my mind ever
            Will condescend to such absurd commands? --Milton.
      [1913 Webster]

            Spain's mighty monarch,
            In gracious clemency, does condescend,
            On these conditions, to become your friend.
                                                  --Dryden.
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   Note: Often used ironically, implying an assumption of
         superiority.
         [1913 Webster]

               Those who thought they were honoring me by
               condescending to address a few words to me. --F.
                                                  W. Robinson.
         [1913 Webster]

   2. To consent. [Obs.]
      [1913 Webster]

            All parties willingly condescended heruento. --R.
                                                  Carew.

   Syn: To yield; stoop; descend; deign; vouchsafe.
        [1913 Webster] Condescendence

WordNet (r) 3.0 (2006):

condescend
    v 1: behave in a patronizing and condescending manner
    2: do something that one considers to be below one's dignity
       [syn: condescend, deign, descend]
    3: debase oneself morally, act in an undignified, unworthy, or
       dishonorable way; "I won't stoop to reading other people's
       mail" [syn: condescend, stoop, lower oneself]
    4: treat condescendingly [syn: patronize, patronise,
       condescend]