1、quack英[kwæk]美[kwæk]，n.江湖郎中; 庸医; (鸭子的)呱呱声，嘎嘎声; 冒牌医生;vi.(鸭子)呱呱叫，嘎嘎叫。2、[例句]Hard-working medical men may come to be almost as mischievous as quacks.辛勤工作的医生可能变成江湖郎中那样的骗子。