An academic is a career college teacher, a professor. Academics live by the rule "publish or perish."
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.
