Gut-course is a slang term that refers to an easy or basic course. If you're looking for a more formal term to use instead of gut-course, then there are several synonyms you can use. For example, you could say "introductory course," "foundational course," or "beginner's course." Additionally, you could use the term "elementary course," "primary course," or "fundamental course." These terms can help you convey the same meaning as gut-course but in a more polished way. No matter which synonym you choose to use, be sure that it best fits the context of the conversation or topic.