Musician still playing after church (7)
I believe the answer is:
cellist
'musician' is the definition.
(cellist is a kind of musician)
'still playing after church' is the wordplay.
'playing' indicates an anagram.
'after' says to put letters next to each other.
'church' becomes 'ce' (abbreviation for Church of England).
'still' is an anagram of 'llist'.
'llist' after 'ce' is 'CELLIST'.
(Other definitions for cellist that I've seen before include "E.g. Casals, du Pre" , "Du Pre or Lloyd Weber" , "String player" , "Lloyd Webber?" , "Member of orchestra" .)