The Collaborative International Dictionary of English v.0.48:

Parliamentary \Par`lia*men"ta*ry\, a. [Cf. F. parlementaire.]
   [1913 Webster]
   1. Of or pertaining to Parliament; as, parliamentary
      authority. --Bacon.
      [1913 Webster]

   2. Enacted or done by Parliament; as, a parliamentary act.
      --Sir M. Hale.
      [1913 Webster]

   3. According to the rules and usages of Parliament or of
      deliberative bodies; as, a parliamentary motion;
      parliamentary order; parliamentary procedure.
      [1913 Webster +PJC]

   Parliamentary agent, a person, usually a solicitor,
      professionally employed by private parties to explain and
      recommend claims, bills, etc., under consideration of
      Parliament. [Eng.]

   Parliamentary train, one of the trains which, by act of
      Parliament, railway companies are required to run for the
      conveyance of third-class passengers at a reduced rate.
      [Eng.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

parliamentary agent
    n 1: a person who is employed to look after the affairs of
         businesses that are affected by legislation of the British
         Parliament