The Collaborative International Dictionary of English v.0.48:

Commoner \Com"mon*er\, n.
   1. One of the common people; one having no rank of nobility.
      [1913 Webster]

            All below them [the peers] even their children, were
            commoners, and in the eye of the law equal to each
            other.                                --Hallam.
      [1913 Webster]

   2. A member of the House of Commons.
      [1913 Webster]

   3. One who has a joint right in common ground.
      [1913 Webster]

            Much good land might be gained from forests . . .
            and from other commonable places, so as always there
            be a due care taken that the poor commoners have no
            injury.                               --Bacon.
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   4. One sharing with another in anything. [Obs.] --Fuller.
      [1913 Webster]

   5. A student in the university of Oxford, Eng., who is not
      dependent on any foundation for support, but pays all
      university charges; - - at Cambridge called a pensioner.
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   6. A prostitute. [Obs.] --Shak.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Pensioner \Pen"sion*er\, n.
   1. One in receipt of a pension; hence, figuratively, a
      dependent.
      [1913 Webster]

            The fickle pensioners of Morpheus' train. --Milton.
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            Old pensioners . . . of Chelsea Hospital.
                                                  --Macaulay.
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   2. One of an honorable band of gentlemen who attend the
      sovereign of England on state occasions, and receive an
      annual pension, or allowance, of [pounds]150 and two
      horses.
      [1913 Webster]

   3. [Cf. F. pensionnaire one who pays for his board. Cf.
      Pensionary, n.] In the university of Cambridge, England,
      one who pays for his living in commons; -- corresponding
      to commoner at Oxford. --Ld. Lytton.
      [1913 Webster]

WordNet (r) 3.0 (2006):

pensioner
    n 1: the beneficiary of a pension fund [syn: pensioner,
         pensionary]

Moby Thesaurus II by Grady Ward, 1.0:

47 Moby Thesaurus words for "pensioner":
   allottee, almsman, almswoman, annuitant, assign, assignee,
   assistant, beneficiary, charge, client, commoner, dependent,
   devisee, donee, employee, encumbrance, exhibitioner, feoffee,
   girl Friday, golden-ager, grantee, hired hand, hired man, hireling,
   legatary, legatee, man Friday, mercenary, myrmidon, optime,
   passman, patentee, pensionary, protege, public charge, questionist,
   right-hand man, senior citizen, servitor, sizar, sophister,
   stipendiary, veteran, ward, worker, wrangler, wrinkly



Bouvier's Law Dictionary, Revised 6th Ed (1856):

PENSIONER. One who is supported by an allowance at the will of another. It
is more usually applied to him who receives an annuity or pension from the
government.