The phrase "complete amount" refers to the total sum of something, often in terms of money or a numerical value. There are several synonyms that can be used in place of this phrase to convey the same meaning, such as "entire sum," "total cost," "full amount," or simply "total." Each of these phrases refers to the complete or whole value of something and can be used interchangeably depending on the context. Using synonyms like these can add variety and interest to your writing while still getting your message across clearly and effectively.