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
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'.