Piece of Purcell is taxing musician (7)
I believe the answer is:
cellist
'musician' is the definition.
(cellist is a kind of musician)
'piece of purcell is taxing' is the wordplay.
'piece of' says the answer is hidden in the clue.
'CELLIST' can be found hidden inside 'purcell is taxing'.
(Other definitions for cellist that I've seen before include "Lloyd Webber?" , "Member of orchestra" , "Du Pre or Lloyd Weber" , "Musician in string section" , "E.g. Casals, du Pre" .)