Conductor’s ear, most refined (7)
I believe the answer is:
maestro
'conductor's' is the definition.
(I've seen this before)
'ear most refined' is the wordplay.
'refined' is an anagram indicator.
'ear'+'most'='earmost'
'earmost' anagrammed gives 'MAESTRO'.
(Other definitions for maestro that I've seen before include "Are most in favour of a foreign master?" , "Outstanding performer" , "ace" , "Rattle, say" , "Virtuoso" .)