North Carolina county whose seat is Jefferson (4)
I believe the answer is:
ashe
'north carolina county whose seat is jefferson' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ashe that I've seen before include "Arthur, first black Wimbledon men's singles champion, 1975" , "He was good enough to win Wimbledon" , "Sporting champion once" , "US rallying champion" , "US tennis player Arthur, 1975 Wimbledon champion" .)