c.1300, wajour "a promise, a vow, something pledged or sworn to;" also "a bet, a wager; stakes, something laid down as a bet," from Anglo-French wageure, Old North French wagiere (Old French gagiere, Modern French gageure) "pledge, security," from wagier "to pledge" (see wage, n.).

c.1600 (intransitive); 1610s (transitive), from wager, n.. Related: Wagered; wagering.