Tennis immortal (4)
I believe the answer is:
ashe
'tennis immortal' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ashe that I've seen before include "US rallying champion" , "Former tennis star" , "Ex-Wimbledon champ" , "Arthur ___, American tennis player 1943-1993" , "Sporting champion once" .)