The Collaborative International Dictionary of English v.0.48:

Discountenance \Dis*coun"te*nance\, n.
   Unfavorable aspect; unfriendly regard; cold treatment;
   disapprobation; whatever tends to check or discourage.
   [1913 Webster]

         He thought a little discountenance on those persons
         would suppress that spirit.              --Clarendon.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Discountenance \Dis*coun"te*nance\, v. t. [imp. & p. p.
   Discountenanced; p. pr. & vb. n. Discountenancing.]
   [Pref. dis- + countenance: cf. OF. descontenancer, F.
   d['e]contenancer.]
   1. To ruffle or discompose the countenance of; to put of
      countenance; to put to shame; to abash.
      [1913 Webster]

            How would one look from his majestic brow . . .
            Discountenance her despised!          --Milton.
      [1913 Webster]

            The hermit was somewhat discountenanced by this
            observation.                          --Sir W.
                                                  Scott.
      [1913 Webster]

   2. To refuse to countenance, or give the support of one's
      approval to; to give one's influence against; to restrain
      by cold treatment; to discourage.
      [1913 Webster]

            A town meeting was convened to discountenance riot.
                                                  --Bancroft.
      [1913 Webster]

WordNet (r) 3.0 (2006):

discountenance
    v 1: look with disfavor on; "The republic soon discountenanced
         its few friends"
    2: show disapproval by discouraging; "any measure tending to
       fuse invalids into a class with special privileges should be
       discountenanced"

Moby Thesaurus II by Grady Ward, 1.0:

74 Moby Thesaurus words for "discountenance":
   abash, abashment, baffle, balk, be against, be agin, blast, brave,
   chagrin, challenge, checkmate, circumvent, confound, confront,
   confuse, confusion, contravene, counter, counteract, countermand,
   counterwork, cross, dash, defeat, defy, deprecate, destroy,
   discomfit, discomfiture, discommend, discomposure, disconcert,
   disconcertion, disconcertment, disesteem, disfavor, dish, disrupt,
   distress, disturbance, elude, embarrassment, faze, flummox, foil,
   frown, frustrate, knock the chocks, mortification, nonplus,
   not abide, not bear with, not brook, not condone, not countenance,
   not endure, not hold with, not stand for, not suffer, not tolerate,
   object, perplex, rattle, reproach, reprove, ruin, sabotage, scotch,
   spike, spoil, stonewall, stump, thwart, upset