Loud stringed instrument or wind instrument (5)
I believe the answer is:
flute
'wind instrument' is the definition.
(I know that flute is a type of woodwind instrument)
'loud stringed instrument' is the wordplay.
'loud' becomes 'f' (short for forte - 'loud' in music).
'stringed instrument' becomes 'lute' (lute is a type of stringed instrument).
'f'+'lute'='FLUTE'
'or' is the link.
(Other definitions for flute that I've seen before include "Wine glass; instrument" , "Blown" , "Musical instrument - wineglass" , "Narrow wineglass" , "Champagne glass" .)