The Collaborative International Dictionary of English v.0.48:

Discomfit \Dis*com"fit\, v. t. [imp. & p. p. Discomfited; p.
   pr. & vb. n. Discomfiting.] [OF. desconfit, p. p. of
   desconfire, F. d['e]confire; fr. L. dis- + conficere to make
   ready, prepare, bring about. See Comfit, Fact.]
   1. To scatter in fight; to put to rout; to defeat.
      [1913 Webster]

            And his proud foes discomfit in victorious field.
                                                  --Spenser.
      [1913 Webster]

   2. To break up and frustrate the plans of; to balk? to throw
      into perplexity and dejection; to disconcert.
      [1913 Webster]

            Well, go with me and be not so discomfited. --Shak.

   Syn: To defeat; overthrow; overpower; vanquish; conquer;
        baffle; frustrate; confound; discourage.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Discomfit \Dis*com"fit\, a.
   Discomfited; overthrown. [Obs.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Discomfit \Dis*com"fit\, n.
   Rout; overthrow; discomfiture.
   [1913 Webster]

         Such a discomfit as shall quite despoil him. --Milton.
   [1913 Webster] discomfited

WordNet (r) 3.0 (2006):

discomfit
    v 1: cause to lose one's composure [syn: upset, discompose,
         untune, disconcert, discomfit]

Moby Thesaurus II by Grady Ward, 1.0:

103 Moby Thesaurus words for "discomfit":
   abash, addle, addle the wits, annoy, appall, astound, baffle, balk,
   ball up, becloud, bedazzle, befuddle, bewilder, blast, bother,
   brave, bug, cast down, chagrin, challenge, check, checkmate,
   circumvent, cloud, confound, confront, confuse, contravene,
   counter, counteract, countermand, counterwork, cross, dash, daze,
   dazzle, defeat, defy, destroy, discombobulate, discompose,
   disconcert, discountenance, dish, dismay, disorganize, disorient,
   disrupt, disturb, elude, embarrass, entangle, faze, flummox,
   flurry, fluster, flutter, fog, foil, frustrate, fuddle, fuss, irk,
   knock the chocks, maze, mist, mix up, moider, mortify, muddle,
   nonplus, outdo, outwit, overcome, panic, perplex, perturb, pother,
   put out, put to flight, put to rout, raise hell, rattle, rout,
   ruffle, ruin, sabotage, scatter, scotch, spike, spoil, stampede,
   stonewall, stump, take aback, throw into confusion, thwart, trump,
   unnerve, unsettle, upset, vex, worry