The Collaborative International Dictionary of English v.0.48:

Baffle \Baf"fle\ (b[a^]f"f'l), v. t. [imp. & p. p. Baffled
   (-f'ld); p. pr. & vb. n. Baffling (-fl[i^]ng).] [Cf.
   Lowland Scotch bauchle to treat contemptuously, bauch
   tasteless, abashed, jaded, Icel. b[=a]gr uneasy, poor, or
   b[=a]gr, n., struggle, b[ae]gja to push, treat harshly, OF.
   beffler, beffer, to mock, deceive, dial. G. b[aum]ppe mouth,
   beffen to bark, chide.]
   [1913 Webster]
   1. To cause to undergo a disgraceful punishment, as a
      recreant knight. [Obs.]
      [1913 Webster]

            He by the heels him hung upon a tree,
            And baffled so, that all which passed by
            The picture of his punishment might see. --Spenser.
      [1913 Webster]

   2. To check by shifts and turns; to elude; to foil.
      [1913 Webster]

            The art that baffles time's tyrannic claim.
                                                  --Cowper.
      [1913 Webster]

   3. To check by perplexing; to disconcert, frustrate, or
      defeat; to thwart. "A baffled purpose." --De Quincey.
      [1913 Webster]

            A suitable scripture ready to repel and baffle them
            all.                                  --South.
      [1913 Webster]

            Calculations so difficult as to have baffled, until
            within a . . . recent period, the most enlightened
            nations.                              --Prescott.
      [1913 Webster]

            The mere intricacy of a question should not baffle
            us.                                   --Locke.
      [1913 Webster]

   Baffling wind (Naut.), one that frequently shifts from one
      point to another.
      [1913 Webster]

   Syn: To balk; thwart; foil; frustrate; defeat.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

baffled \baffled\ adj.
   not understanding.

   Syn: uncomprehending.
        [WordNet 1.5]

   2. discouraged by failure to accomplish a goal and uncertain
      how to proceed; -- used especially of feelings of defeat
      and discouragement.

   Syn: balked, discomfited, discouraged, frustrated.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

baffled
    adj 1: perplexed by many conflicting situations or statements;
           filled with bewilderment; "obviously bemused by his
           questions"; "bewildered and confused"; "a cloudy and
           confounded philosopher"; "just a mixed-up kid"; "she felt
           lost on the first day of school" [syn: baffled,
           befuddled, bemused, bewildered, confounded,
           confused, lost, mazed, mixed-up, at sea]
    n 1: people who are frustrated and perplexed; "the children's
         faces clearly expressed the frustration of the baffled"

Moby Thesaurus II by Grady Ward, 1.0:

51 Moby Thesaurus words for "baffled":
   addled, at a loss, at a nonplus, at a stand, at a standstill,
   at an impasse, balked, bamboozled, beat, betrayed, bewildered,
   bilked, blasted, blighted, buffaloed, chapfallen, confounded,
   crestfallen, crossed, crushed, dashed, dazed, defeated,
   disappointed, dished, disillusioned, dissatisfied, floored, foiled,
   frustrated, fuddled, ill done-by, ill-served, in a dilemma,
   in suspense, let down, licked, muddled, mystified, nonplussed,
   on tenterhooks, out of countenance, perplexed, puzzled, regretful,
   sorely disappointed, soured, stuck, stumped, thrown, thwarted