He was exposed as a charlatan.

他这个假行家被曝了光。

《柯林斯英汉双解大词典》

A charlatan murders without a knife.

庸医杀人不用刀。

《新英汉大辞典》

A fraudster a charlatan and a thief.

一个骗子，一个吹牛者，还是一个贼。

youdao

But the last thing it needs are the quack remedies of a charlatan whose real intention is to kill the patient.

BBC: Charles Kennedy

But State, backed by CIA officials, says Chalabi is a charlatan who hasn't lived in Iraq since 1958 and has no constituency there.

CNN: Clash of the administration titans

This appeal always frustrated his political opponents - although there are others who argue Sheridan has never been anything other than a charlatan.

BBC: The rise and fall of Tommy Sheridan and the left