Someone from north of the border? (4)
I believe the answer is:
scot
'someone from north of the border?' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for scot that I've seen before include "Tax, Glasgow native" , "Highlander, for example" , "National" , "Aberdonian perhaps" , "A Caledonian?" .)