The Collaborative International Dictionary of English v.0.48:

Retire \Re*tire"\, v. t. [imp. & p. p. Retired; p. pr. & vb.
   n. Retiring.] [F. retirer; pref. re- re- + tirer to draw.
   See Tirade.]
   1. To withdraw; to take away; -- sometimes used reflexively.
      [1913 Webster]

            He . . . retired himself, his wife, and children
            into a forest.                        --Sir P.
                                                  Sidney.
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            As when the sun is present all the year,
            And never doth retire his golden ray. --Sir J.
                                                  Davies.
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   2. To withdraw from circulation, or from the market; to take
      up and pay; as, to retire bonds; to retire a note.
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   3. To cause to retire; specifically, to designate as no
      longer qualified for active service; to place on the
      retired list; as, to retire a military or naval officer.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Retiring \Re*tir"ing\, a.
   1. Reserved; shy; not forward or obtrusive; as, retiring
      modesty; retiring manners.
      [1913 Webster]

   2. Of or pertaining to retirement; causing retirement; suited
      to, or belonging to, retirement.
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   Retiring board (Mil.), a board of officers who consider and
      report upon the alleged incapacity of an officer for
      active service.

   Retiring pension, a pension granted to a public officer on
      his retirement from office or service.
      [1913 Webster]

WordNet (r) 3.0 (2006):

retiring
    adj 1: not arrogant or presuming; "unassuming to a fault,
           skeptical about the value of his work"; "a shy retiring
           girl" [syn: retiring, unassuming]
    2: of a person who has held and relinquished a position or
       office; "a retiring member of the board" [syn: past(a),
       preceding(a), retiring(a)]
    3: reluctant to draw attention to yourself [syn: reticent,
       self-effacing, retiring]

Moby Thesaurus II by Grady Ward, 1.0:

106 Moby Thesaurus words for "retiring":
   Olympian, aloof, aseptic, backward, bashful, blank, boat-shaped,
   boatlike, bowl-shaped, bowllike, cavelike, cavernous, chilled,
   chilly, cold, concave, concaved, constrained, cool, coy,
   craterlike, cup-shaped, cupped, cymbiform, declining, demure,
   detached, diffident, diminishing, discreet, dish-shaped, dished,
   dishing, dishlike, distant, dwindling, dying, ebbing,
   expressionless, fading, forbidding, frigid, frosty,
   funnel-breasted, funnel-chested, funnel-shaped, guarded, hollow,
   hollowed, humble, icy, impassive, impersonal, inaccessible,
   incurved, incurving, incurvous, infundibular, infundibuliform,
   introverted, meek, modest, navicular, naviform, offish, quiet,
   rabbity, receding, reclusive, remote, removed, repressed, reserved,
   restrained, reticent, retreating, saucer-shaped, scaphoid,
   scyphate, self-effacing, shrinking, shy, sinking, spoonlike,
   standoff, standoffish, subdued, sunk, sunken, suppressed, timid,
   timorous, unaffable, unapproachable, unassertive, unassuming,
   unassured, uncongenial, undemonstrative, unexpansive, ungenial,
   unpretentious, unsociable, unsocial, waning, withdrawn