Rap hits, possibly, for a musician (7)
I believe the answer is:
harpist
'for a musician' is the definition.
(harpist is a kind of musician)
'rap hits possibly' is the wordplay.
'possibly' indicates anagramming the letters.
'rap'+'hits'='raphits'
'raphits' anagrammed gives 'HARPIST'.
(Other definitions for harpist that I've seen before include "Stringed instrument player" , "musician" , "Instrumentalist" .)