Decaying rubbish found before sound of bell (7)
I believe the answer is:
rotting
'decaying' is the definition.
(I know that decaying can be written as rotting)
'rubbish found before sound of bell' is the wordplay.
'rubbish' becomes 'rot' (both can mean nonsense).
'found before' says to put letters next to each other.
'sound of bell' becomes 'ting' (I've seen this in other clues).
'rot'+'ting'='ROTTING'
(Other definitions for rotting that I've seen before include "Sultanate in NW Borneo" , "Putrid" , "Going bad" , "Decaying" , "corruption?" .)