Yesterday my Ascend day started with a lab, not lecture, so I was pleasantly surprised to arrive half an hour before it started to discover three or four people settled into the room already. I told them I was glad to have a few keeners in the class and got nothing but puzzled looks for my trouble. It seems it's a Canadian slang that hasn't spread very far. Tonight I Googled a little - it's hard, because it's a commonish last name, plus people insist on taking “a keener look” or having “a keener focus” and the like. But the only sites I could find that used it to mean “someone who studies way harder than everyone else, does all their homework, and always puts schoolwork above leisure, socializing or sleep” were Canadian ones.
Was I a keener as an undergrad? Oh yes. But I was in Engineering, rich in keeners depite the hard-partying image. I wasn't the keenest of them all or anything like that. It's served me in good stead, though. You would be amazed what you can do with your brain if you're just determined to do it.