someone who pretends to be someone or something that they are not, or to be able to do something that they cannot

The university was divided into those people who thought he was a genius and those who thought he was a mountebank. 大学分成了两派，一派认为他是天才，另一派认为他是个江湖骗子。

The potion was dispensed by both physicians and itinerant mountebanks. 药水是医生和游走各处的江湖骗子一起炮制的。