If you call someone a prig, you disapprove of them because they behave in a very moral way and disapprove of other people's behaviour as though they are superior.
英汉词典释义
n.
一本正经的人
He had been railed against by them as a prig and a poseur.他们责骂他是一个沾沾自喜、装腔作势的人。