The Collaborative International Dictionary of English v.0.48:

Proscribe \Pro*scribe"\, v. t. [imp. & p. p. Proscribed; p.
   pr. & vb. n. Proscribing.] [L. proscribere, proscriptum, to
   write before, to publish, proscribe; pro before + scribere to
   write. See Scribe. The sense of this word originated in the
   Roman practice of writing the names of persons doomed to
   death, and posting the list in public.]
   1. To doom to destruction; to put out of the protection of
      law; to outlaw; to exile; as, Sylla and Marius proscribed
      each other's adherents.
      [1913 Webster]

            Robert Vere, Earl of Oxford, . . . was banished the
            realm, and proscribed.                --Spenser.
      [1913 Webster]

   2. To denounce and condemn; to interdict; to prohibit; as,
      the Puritans proscribed theaters.
      [1913 Webster]

            The Arian doctrines were proscribed and
            anathematized in the famous Council of Nice.
                                                  --Waterland.
      [1913 Webster]

WordNet (r) 3.0 (2006):

proscribe
    v 1: command against; "I forbid you to call me late at night";
         "Mother vetoed the trip to the chocolate store"; "Dad nixed
         our plans" [syn: forbid, prohibit, interdict,
         proscribe, veto, disallow, nix] [ant: allow,
         countenance, let, permit]