Musical girl (5)
I believe the answer is:
annie
I believe this clue is a double definition.
'musical' is the first definition.
(Annie is a Broadway musical)
'girl' is the second definition.
(Other definitions for annie that I've seen before include "Miss Laurie" , "Musical inspired by comic strip" , "Oakley, Laurie or Hall" , "Inane (anag) - girl (with a gun?)" , "-- Oakley (Wild West)" .)