Pay back is an expression that can be used to describe a variety of actions. EXCHANGE (8 letters) is the act of trading one thing for another, while RETALIATE (9 letters) is the act of responding to an action with a similar action. COMPENSATE (10 letters) is the act of providing something of value in return for a service or loss, and TRADE (5 letters) is the act of exchanging goods or services. GET (3 letters) is the act of obtaining something, ola (3 letters) is an acronym for online labor EXCHANGE, opens (5 letters) is the act of beginning something, REMIT (5 letters) is the act of sending money, REPAY (5 letters) is the act of returning money, AVENGE (6 letters) is the act of taking revenge, REFUND (6 letters) is the act of returning money, REQUITE (7 letters) is the act of returning a favor, makegood (8 letters) is the act of making up for a mistake, REIMBURSE (9 letters) is the act of returning money, and revengeon (9 letters) is the act of taking revenge on someone. All of these terms can be used to describe the concept of pay back.