The word "Nat" is typically used as a nickname or short form for names such as Nathan, Nathaniel, or Natalie. However, there are a few synonyms that can be used as alternatives to "Nat" in certain contexts. For example, "Nate" is a common alternative for Nathan or Nathaniel, while "Natasha" or "Talia" can be used as substitutes for Natalie. Other options may depend on the specific name and context - for instance, "Nate Dogg" was a famous rapper who went by his nickname, while "Natty" can be used as a shortened form of the Jamaican name "Nathaniel." Ultimately, the best synonym for "Nat" will depend on the individual in question and the context in which the name is being used.