Sportsman to drive off (5)
I believe the answer is:
diver
'sportsman' is the definition.
(I know that diver is a type of sportsman)
'drive off' is the wordplay.
'off' indicates an anagram.
'drive' with letters rearranged gives 'DIVER'.
'to' is the link.
(Other definitions for diver that I've seen before include "Drive (anag.)" , "Competitor in pool" , "Underwater worker" , "One jumping off board" , "Large waterbird" .)