Oxbridge slang for someone who is 'superkeen'; that is, keener than keen. Associated with a strong go-getting attitude, but one that is obvious and public, to the point of being awkwardly endearing or backfiring.
Unclear where 'nadster' originates from. Likely related to nads, as in someone who's "got balls", or the Polish 'nad', meaning 'above' - say, 'above keen'.
"Let's try and be first into the club!"
"Nah, nobody's in there. We'll end up floating around like abandoned toilet paper. Don't want to be super-keen nadsters."
"I looked at the slogan I'd painted up on the banner: 'Come on lads, be a nads(ter)!!'. What was I thinking? The pun didn't even make sense. I looked like such a super-keen nadster."
An absolutely foolproof way to keep minors from viewing content deemed "too mature" for them to watch.
Billy: "So I was trying to watch some videos for an M rated game, and I ran into an age gate, so I put in my real birthday. SOMEHOW it managed to figure out that I am 12. CURSE YOU AGE GATE!!!"
Bill: "Fucking age gate! *quick scroll* THERE! I was born on January 1, 1904. Fuck you age gate."