Piece of music without vocals (12)
I believe the answer is:
instrumental
'piece of music without vocals' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for instrumental that I've seen before include "Acting as a means; piece of music without vocals" , "Helpful; composition" , "Piece of music without voices" , "case" , "Having some responsibility - not vocal" .)