informal a tout at an auction, sideshow, etc., who calls out to passers-by to attract custom
〈非正式〉（在拍卖会、马戏团穿插表演上）大声招徕顾客者。
词源
late Middle English: from BARK1 + -ER1. The original sense was 'a person or animal that barks; noisy protestor'， hence the current sense （late 17th cent.）.