The con artist was finally revealed as a complete fake when his credentials were checked.

fake 是名词，意思是"假货、赝品、冒充者"，指不是真实或合法的人或事物。这个词也可以作形容词，表示"假的、伪造的"。在句中作为名词使用，指那个骗子是个彻头彻尾的冒牌货。