What is a person who pretends to be something they are not called?

The term "poseur" accurately captures the essence of someone who pretends to be something they are not, often in a way that is intended to create a false impression or to gain social acceptance. A poseur typically adopts a persona, style, or identity that does not genuinely reflect their true self, often to seem more sophisticated, cultured, or appealing to others.

While "fraud," "imposter," and "phony" also refer to forms of deception or misrepresentation, they each carry slightly different connotations. "Fraud" implies a legal or financial connotation, suggesting dishonest practices for gain. "Imposter" often refers specifically to someone who impersonates another individual with the intention of deceit. "Phony," on the other hand, describes someone who is insincere or fake but may not necessarily imply an active pretense of a different identity. Thus, "poseur" is the most fitting choice when describing someone engaged in pretension for social purposes.