The Collaborative International Dictionary of English v.0.48:

Reimburse \Re`im*burse"\ (-b?rs"), v. t. [imp. & p. p.
   Reimbursed (-b?rst"); p. pr. & vb. n. Reimbursing.]
   [Pref. re- + imburse: cf. F. rembourser.]
   1. To replace in a treasury or purse, as an equivalent for
      what has been taken, lost, or expended; to refund; to pay
      back; to restore; as, to reimburse the expenses of a war.
      [1913 Webster]

   2. To make restoration or payment of an equivalent to (a
      person); to pay back to; to indemnify; -- often reflexive;
      as, to reimburse one's self by successful speculation.
      --Paley.
      [1913 Webster]

WordNet (r) 3.0 (2006):

reimburse
    v 1: pay back for some expense incurred; "Can the company
         reimburse me for my professional travel?"
    2: reimburse or compensate (someone), as for a loss [syn:
       recoup, reimburse]

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "reimburse":
   atone, balance, compensate, give satisfaction, indemnify,
   kick back, make amends, make good, make reparation,
   make restitution, make up for, make up to, offset, pay, pay back,
   pay damages, pay in kind, quit, recompense, recoup, recover,
   redress, refund, remunerate, repay, requite, square