ˈri(ə)rˌwȯrd, ˈriəˌwȯ(ə)d noun
Etymology: Middle English rerewarde, from Anglo-French, from Old French rere backward, behind + Old North French warde guard; akin to Old French garde, guarde guard — more at retro- , guard
obsolete : rear guard
the Lord will go before you; and the God of Israel will be your rereward — Isa 52:12 (Authorized Version)