VERB (3)

1. help to readapt, as to a former state of health or good repute;
- Example: "The prisoner was successfully rehabilitated"
- Example: "After a year in the mental clinic, the patient is now rehabilitated"

2. reinstall politically;
- Example: "Deng Xiao Ping was rehabilitated several times throughout his lifetime"

3. restore to a state of good condition or operation;

The Collaborative International Dictionary of English v.0.48:

Rehabilitate \Re`ha*bil"i*tate\ (r?`h?*b?l"?*t?t), v. t. [imp. &
   p. p. Rehabilitated (-t?`t?d); p. pr. & vb. n.
   Rehabilitating.] [Pref. re- re- + habilitate: cf. LL.
   rehabilitare, F. r['e]habiliter.]
   To invest or clothe again with some right, authority, or
   dignity; to restore to a former capacity; to reinstate; to
   qualify again; to restore, as a delinquent, to a former
   right, rank, or privilege lost or forfeited; -- a term of
   civil and canon law.
   [1913 Webster]

         Restoring and rehabilitating the party.  --Burke.
   [1913 Webster]

WordNet (r) 3.0 (2006):

rehabilitate
    v 1: help to readapt, as to a former state of health or good
         repute; "The prisoner was successfully rehabilitated";
         "After a year in the mental clinic, the patient is now
         rehabilitated"
    2: reinstall politically; "Deng Xiao Ping was rehabilitated
       several times throughout his lifetime" [ant: purge]
    3: restore to a state of good condition or operation

Moby Thesaurus II by Grady Ward, 1.0:

56 Moby Thesaurus words for "rehabilitate":
   account for, change, clear, cry sour grapes, destigmatize,
   do justice to, exculpate, explain, fix up, give back, justify,
   place in, purge, put back, rationalize, reactivate, rebuild,
   reclaim, recondition, reconstitute, reconstruct, reconvert,
   recover, recruit, redecorate, redeem, reeducate, reenact,
   reestablish, refill, reform, refurbish, reinstall, reinstate,
   reinstitute, reinstruct, reintegrate, reinvest, rejuvenate, renew,
   renovate, reorient, repair, repatriate, replace, replenish, rescue,
   restitute, restore, return, revest, save, straighten out,
   transform, vindicate, warrant