Formal:
* Natural Scientist: This is the most direct and straightforward term.
* Natural Philosopher: This term is more historical, but still used sometimes.
* Scientist: This is a general term that encompasses both natural and social scientists.
Informal:
* Biologist, chemist, physicist, geologist, astronomer: These are more specific terms for scientists in different fields of natural science.
* Researcher, scholar: These terms are more general and can be used for natural scientists, but also other academic professionals.
The best word to use depends on the context and the specific field of natural science you are referring to.
