The phrase "heavy money" is commonly used to describe large amounts of cash or wealth. However, there are several synonyms that can be used to convey the same meaning. For example, "fat stack" is a slang term used to describe a large sum of money. "Big bucks" or "serious dough" are also common phrases used to describe substantial amounts of money. "Wealthy," "affluent," and "prosperous" are adjectives that can be used to describe individuals or entities with significant financial resources. In summary, there are several synonyms that can be used to describe "heavy money," ranging from slang terms to formal vocabulary.