Instrument accompanying singer with nothing on? (7)
I believe the answer is:
bassoon
'instrument' is the definition.
(type of musical instrument)
'accompanying singer with nothing on?' is the wordplay.
'accompanying' means one lot of letters go next to another.
'singer' becomes 'bass' (bass is a kind of singer).
'with' says to put letters next to each other.
'nothing' becomes 'O' (O resembles 0).
'bass'+'o'='basso'
'basso' next to 'on' is 'BASSOON'.
(Other definitions for bassoon that I've seen before include "No, a boss would be a musical instrument" , "Low wind instrument" , "wind player" , "Instrument - no ASBOs (anag)" , "Large woodwind instrument" .)