noun:
1.exceptional intellectual or creative power or other natural ability.
2.an exceptionally intelligent person or one with exceptional skill in a particular area of activity.
So that's somebody who's creative, OR (and the or is important) has natural ability in something - they can do things easily on there first couple of tries - OR someone who is incredibly intellectual.
Second definition kind of means the same as the first one but that person must have a skill that they exceed non-geniuses at (at that field).
After googling, I found that to be a genius, you must have an IQ of 140+ (found from one site) or 160+ (found from another site).
Example: Lionel Messi is a genius because he's been proven to be the best footballer (soccer player) (although it's opinion) in the world for the past 4 years. Stephen Hawkins is incredibly intellectual and is an expert in his field; he is a genius. Leonardo Da Vinci was a very creative person and he was a master in his field.
Conclusion: You can be a genius if you're not "book smart". You are a genius if you are better than every non-genius in your field.
On topic: I find things quite easy on my first couple of goes (mathematics, football [soccer], karate, reading etc) but I am not an expert in any of these fields (or at least I'm not yet). I haven't had an IQ test before. So, even if I am a genius, I have no proof. As for being a hard worker, I tend to work harder in some fields rather than others and only if I see a worthwhile reward or that I enjoy the thing I'm working on.
Lecture over.
