Gong heard finally interrupting dinner? (5)
I believe the answer is:
medal
'gong' is the definition.
(gong can mean a prize or medal)
'heard finally interrupting dinner?' is the wordplay.
'finally' indicates one should take the final letters.
'interrupting' is an insertion indicator.
'dinner?' becomes 'meal' (dinner is a meal).
The last letter of 'heard' is 'd'.
'd' going within 'meal' is 'MEDAL'.
(Other definitions for medal that I've seen before include "Piece of metal as award or in commemoration" , "Metal disc awarded as prize, say in Olympics" , "Lamed (anag)" , "Award for achievement" , "Small metal disc as reward or prize" .)