The phrase "threedollar bills" is commonly used as a slang term to describe something that is fake or fraudulent. Synonyms for this phrase include "counterfeit," "phony," "fraudulent," "fake," and "bogus." These words all convey a sense of deception or falseness, and can be used to describe anything from a fraudulent product to a dishonest individual. Other related phrases that may be used to describe something fake or fraudulent include "snake oil," "scam," "rip-off," "hoax," and "con job." It's important to be aware of these common phrases and their meanings to avoid being taken advantage of in any situation.