The Collaborative International Dictionary of English v.0.48:

Retirement \Re*tire"ment\, n. [Cf. F. retirement.]
   1. The act of retiring, or the state of being retired;
      withdrawal; seclusion; as, the retirement of an officer.
      [1913 Webster]

            O, blest Retirement, friend of life's decline.
                                                  --Goldsmith.
      [1913 Webster]

            Retirement, rural quiet, friendship, books.
                                                  --Thomson.
      [1913 Webster]

   2. A place of seclusion or privacy; a place to which one
      withdraws or retreats; a private abode. [Archaic]
      [1913 Webster]

            This coast full of princely retirements for the
            sumptousness of their buildings and nobleness of the
            plantations.                          --Evelyn.
      [1913 Webster]

            Caprea had been the retirement of Augustus.
                                                  --Addison.
      [1913 Webster]

   Syn: Solitude; withdrawment; departure; retreat; seclusion;
        privacy. See Solitude.
        [1913 Webster]

WordNet (r) 3.0 (2006):

retirement
    n 1: the state of being retired from one's business or
         occupation
    2: withdrawal from your position or occupation
    3: withdrawal for prayer and study and meditation; "the
       religious retreat is a form of vacation activity" [syn:
       retirement, retreat]

Moby Thesaurus II by Grady Ward, 1.0:

219 Moby Thesaurus words for "retirement":
   Jim Crow, abandonment, abdication, abstention, abstinence,
   acquitment, acquittal, acquittance, aloofness, amortization,
   amortizement, anonymity, apartheid, apartness, backwardness,
   bashfulness, binder, blankness, cash, cash payment, cashiering,
   chilliness, clearance, closed meeting, coldness, confidentiality,
   confidentialness, conge, constraint, convenience, coolness,
   debt service, decampment, deconsecration, defrayal, defrayment,
   defrocking, demission, departure, deposal, deposit, deposition,
   deprivation, desuetude, detachment, dethronement, disbarment,
   disbarring, disbursal, discharge, discreetness, discretion,
   discrownment, disemployment, disengagement, disenthronement,
   dismissal, displacement, displacing, distance, disuse, doling out,
   down payment, drumming out, earnest, earnest money, ease, egress,
   emeritus status, escape, evacuation, excommunication,
   executive session, exit, exodus, expressionlessness, expulsion,
   fallback, firing, flight, forced resignation, forced separation,
   free time, freedom, frigidity, frostiness, furloughing, getaway,
   going, goof-off time, guardedness, hegira, hire purchase,
   hire purchase plan, iciness, idle hours, impassiveness,
   impassivity, impeachment, impersonality, inaccessibility,
   incognito, installment, installment plan, interest payment,
   introversion, isolation, isolationism, kicking upstairs, layoff,
   leaving, leisure, liquidation, modesty, monthly payments,
   never-never, nonemployment, nonprevalence, nonuse, obsolescence,
   obsoleteness, obsoletion, obsoletism, odd moments, ousting,
   overthrow, overthrowal, parting, passing, paying, paying off,
   paying out, paying up, payment, payment in kind, payoff,
   pensioning off, pink slip, prepayment, privacy, private conference,
   privatism, privatization, pullback, pullout, purge, quarantine,
   quarterly payments, quittance, recedence, receding, recess,
   recession, reclusion, reculade, regular payments, relinquishment,
   remittance, remoteness, removal, repose, repression, reserve,
   reservedness, resignation, rest, restraint, reticence, reticency,
   retiral, retractation, retractility, retraction, retreat,
   retrocedence, rustication, satisfaction, seclusion, secrecy,
   segregation, semiretirement, separation, sequestration, settlement,
   sinking-fund payment, spare time, splendid isolation, spot cash,
   standoffishness, subduedness, superannuation, suppression,
   surplusing, suspension, the ax, the boot, the bounce, the gate,
   the sack, ticket, time, time to kill, time to spare, unaffability,
   unapproachability, unchurching, uncongeniality,
   undemonstrativeness, unexpansiveness, unfrocking, unprevalence,
   unseating, voluntary resignation, walking papers, walkout,
   weekly payments, withdrawal, withdrawment, withdrawnness