A Ponzi scheme is a fraudulent investment operation that pays returns to its investors from the capital of new investors rather than from profit earned. Synonyms for Ponzi include "Ponzi pyramid," "pyramid scheme," "pyramid fraud," or a "chain referral." Other synonyms for Ponzi include "multi-level marketing," which is a legitimate business model that operates as a pyramid but offers legitimate products, and "affinity fraud," a type of Ponzi scheme that targets a particular group, such as a specific religion, ethnicity, or profession. It is crucial to recognize the red flags and avoid falling for Ponzi schemes by doing thorough research and due diligence.