For all players, express disapproval with note (5)
I believe the answer is:
tutti
'for all players' is the definition.
(musical instruction)
'express disapproval with note' is the wordplay.
'express disapproval' becomes 'tut' (tutting is making a disapproving sound).
'with' means one lot of letters go next to another.
'note' becomes 'ti' (musical note, as in do re mi so fa la ti do).
'tut'+'ti'='TUTTI'
(Other definitions for tutti that I've seen before include "All (stage direction)" , "Everyone join in (mus.)" , "All performers (mus.)" , "Orchestral passage" , "Everybody (mus.)" .)