由来是合成词bar+词根gain，中文意思是n. 便宜货，减价品协议，交易，v. 讨价还价，谈判

Buyers will bargain hard to cut the cost of the house they want.买主会竭力讨价还价以压低他们想买的房子的价格。

He reached a plea bargain with the authorities.他和当局达成了辩诉交易。