Singer on love supported by woodwind instrument (7)
I believe the answer is:
bassoon
'woodwind instrument' is the definition.
(bassoon is a kind of woodwind instrument)
'singer on love supported by' is the wordplay.
'singer' becomes 'bass' (bass is a kind of singer).
'on' is a charade indicator (letters next to each other).
'love' becomes 'o' (love means zero in tennis).
'supported by' becomes 'on' (something on something else is supported by it).
'bass'+'o'+'on'='BASSOON'
(Other definitions for bassoon that I've seen before include "Instrument - no ASBOs (anag)" , "Tenor of the oboe family" , "wind player" , "Instrument heard by Wedding-Guest" , "So-so ban over the instrument" .)