WordNet (r) 3.0 (2006):

give back
    v 1: pay back; "Please refund me my money" [syn: refund,
         return, repay, give back]

Moby Thesaurus II by Grady Ward, 1.0:

39 Moby Thesaurus words for "give back":
   back out, backtrack, backwater, bring back, crumble, extradite,
   fail, fall back, falter, place in, put back, reactivate, recommit,
   reconstitute, reconvert, recruit, reenact, reestablish, refill,
   reform, rehabilitate, reinstall, reinstate, reinstitute,
   reintegrate, reinvest, remand, remit, repatriate, replace,
   replenish, restore, retire, return, revest, send back, take back,
   weaken, withdraw