Cassius Marcellus Clay was a famous boxer and civil rights activist. Over the years, he has been referred to by a number of different names due to his changing personal beliefs and lifestyle. Synonyms for Cassius Marcellus Clay include The Greatest, The Louisville Lip, Muhammad Ali, and even simply Ali. Each of these names represents a different aspect of Cassius Marcellus Clay's life, from his skill as a boxer to his outspoken nature. Regardless of the name used, Cassius Marcellus Clay will always be remembered for his contributions to the world of sports and civil rights.