The Collaborative International Dictionary of English v.0.48:

Bar \Bar\ (b[aum]r), v. t. [imp. & p. p. Barred (b[aum]rd); p.
   pr. & vb. n. Barring.] [ F. barrer. See Bar, n.]
   1. To fasten with a bar; as, to bar a door or gate.
      [1913 Webster]

   2. To restrict or confine, as if by a bar; to hinder; to
      obstruct; to prevent; to prohibit; as, to bar the entrance
      of evil; distance bars our intercourse; the statute bars
      my right; the right is barred by time; a release bars the
      plaintiff's recovery; -- sometimes with up.
      [1913 Webster]

            He barely looked the idea in the face, and hastened
            to bar it in its dungeon.             --Hawthorne.
      [1913 Webster]

   3. To except; to exclude by exception.
      [1913 Webster]

            Nay, but I bar to-night: you shall not gauge me
            By what we do to-night.               --Shak.
      [1913 Webster]

   4. To cross with one or more stripes or lines.
      [1913 Webster]

            For the sake of distinguishing the feet more
            clearly, I have barred them singly.   --Burney.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

barring \bar"ring\ n.
   the act of excluding someone by a negative vote or veto.

   Syn: blackball.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

barring
    n 1: the act of excluding someone by a negative vote or veto
         [syn: barring, blackball]

Moby Thesaurus II by Grady Ward, 1.0:

52 Moby Thesaurus words for "barring":
   aside from, ban, bar, beside, besides, blockade, boycott, but,
   circumscription, debarment, debarring, demarcation, discounting,
   embargo, ex, except, except for, excepting, exception,
   exception taken of, excluding, exclusion, exclusive of, from,
   inadmissibility, injunction, leaving out, less, let alone, lockout,
   minus, narrowing, nonadmission, not counting, off, omission,
   omitting, outside of, precluding, preclusion, prohibition,
   rejection, relegation, repudiation, restriction, save,
   save and except, saving, taboo, than, unless, without