Interfere with gong's sound (6)
I believe the answer is:
meddle
'interfere with' is the definition.
(I've seen this before)
'gong's sound' is the wordplay.
'gong' becomes 'medal' (I've seen this before).
'sound' shows a homophone (sound like).
'medal' is a homophone of 'MEDDLE'.
(Other definitions for meddle that I've seen before include "Interfere in the affairs of others" , "Interfere in another's business" , "Pink Floyd album" , "Stick one's nose in" , "Interfere in other people's business" .)