Isolde's love (7)
I believe the answer is:
tristan
'isolde's love' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tristan that I've seen before include "Boy!" , "Isolde's lover" , "operatic role" , "- da Cunha, S. Atlantic island" , "operatic hero" .)