mid-14c., "a regarding, heeding, observation," from Anglo-French and Old North French reward, back-formation from rewarder (see reward (v.)). Meaning "repayment for some service" is from late 14c. Sense of "sum of money in exchange for capture" is from 1590s.
c. 1300 "to grant, bestow;" early 14c. "to give as compensation," from Old North French rewarder "to regard, reward" (Old French regarder) "take notice of, regard, watch over," from re-, intensive prefix (see re-), + warder "look, heed, watch," from a Germanic source, from Proto-Germanic *wardon "to guard" (from PIE root *wer- (3) "perceive, watch out for"). Originally any form of requital. A doublet of regard. Related: Rewarded; rewarding.