Tum-tum is a colloquial term that is often used to describe the stomach or belly. However, there are many synonyms that can be used instead of tum-tum. These include terms like abdomen, belly, gut, midriff, and tummy. Additionally, there are more informal synonyms like beer gut, potbelly, and spare tire. Some people may also use slang terms like breadbasket, chowbox, or grub pouch to refer to their stomach. Overall, there are many different synonyms that can be used instead of tum-tum depending on the context or the level of formality required.