Cut short a large musical work (3)
I believe the answer is:
lop
'cut short' is the definition.
(I've seen this in another clue)
'a large musical work' is the wordplay.
'a large' becomes 'L' (eg in clothes sizes).
'musical work' becomes 'op' (abbreviation for opus).
'l'+'op'='LOP'
(Other definitions for lop that I've seen before include "Cut off, tree branches say" , "Cut away branches or twigs" , "Remove branches from a tree" , "Cut (e.g. branch off)" , "Prune, cut the top off" .)