You can describe someone as a poseur when you think that they behave in an insincere or exaggerated way because they want to make a particular impression on other people.
例句
I am sometimes accused of being an inveterate poseur.有时有人说我惯于装模作样。
英汉词典释义
n.
装腔作势的人
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。
英英词典释义
Noun
1. a person who habitually pretends to be something he is not