What is casual / hardcore player?

[Nero]

I really think the only difference is time spent playing, and even then, there's no hard and fast rule that divides the two. Someone could play hardcore for 3 months and switch to playing casually for the next 5 years, for example.

I understand your Point, but also if we would say "Someone could play hardcore for 3 months and switch...".. what exactly does it mean: "could play hardcore"? That is actually the Mainquestion here.. while i dont have much Time to spend i would be efficient Casualgamer? So if that would be the case, what would be the difference between me and a Hardcoreplayer?