Something that is academic is related to school. Your parents might want to spend less time playing video games and more time focusing on academic pursuits. The noun academic refers to a professor or scholar.
As a noun or an adjective, academic relates to book learning and not always in a good way. An academic discussion back in Plato's Academy was probably something better than what it has more recently come to mean: a discussion that's academic has no place in the real world; it's not practical. An academic might have a PhD in Robotics but not know how to work the TV. It doesn't have to mean stuffy, though, just related to college — like when you need an academic gown for graduation.