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

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

Parnassus is a mystic, or maybe he's a charlatan traveling through modern-day London, England, with his antiquated sideshow, replete with a band of misfits and a magical mirror.

CNN: The making of 'The Imaginarium of Doctor Parnassus'

They needed two crushing electoral defeats to begin revising their view of Mr Blair as a weightless charlatan whom voters would quickly see through.

ECONOMIST: Bagehot