The phrase "pass off as" is commonly used to describe the act of convincing someone that something is true or genuine when it is not. There are a number of synonyms that can be used in place of "pass off as", including "pretend", "feign", "simulate", "fabricate", "misrepresent", and "deceive". Each of these words conveys the idea of presenting something false as true, and can be used in a wide range of contexts. It is important to choose the right synonym based on the specific situation and tone of the message being conveyed.