The immortal love racket (4)
I believe the answer is:
odin
'the immortal' is the definition.
(Odin is an example)
'love racket' is the wordplay.
'love' becomes 'o' (love means zero in tennis).
'racket' becomes 'din' (both can mean a loud noise or disturbance).
'o'+'din'='ODIN'
(Other definitions for odin that I've seen before include "an all-powerful one" , "Chief Norse god" , "I nod to the Norse deity" , "Legendary ruler" , "Supreme Scandinavian god - what a racket" .)