Coppers accepting an act of contrition (7)
I believe the answer is:
penance
'act of contrition' is the definition.
(I've seen this before)
'coppers accepting an' is the wordplay.
'coppers' becomes 'pence' (I've seen this before).
'accepting' indicates putting letters inside.
'pence' going around 'an' is 'PENANCE'.
(Other definitions for penance that I've seen before include "Self-inflicted punishment for wrongdoing" , "Act of atonement" , "Punishment for religious wrongdoing" , "sackcloth and ashes?" , "Punishment for wrongdoing, by religion perhaps" .)