The word "stuff" can be quite vague and often used when we cannot accurately identify something. But sometimes, precision is vital, and we need to replace "stuff" with more precise terms. Generally, the synonym of "stuff" depends on the context in which it is used. Some appropriate synonyms include "material," "substance," or "commodity." Alternatively, if you're referring to a specific type of stuff, you might say "belongings," "equipment," or "supplies." Another option is to refer to something as "things," "objects," or "items," which gives a little more detail, but still not too specific. In short, choosing the right synonym for "stuff" relies on what you're referring to and the level of detail necessary.