Feeling regret for one’s sins (8)
I believe the answer is:
penitent
'feeling regret for one's sins' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for penitent that I've seen before include "Teen pint (anag.)" , "Showing regret" , "I'm sorry" , "Conscience-stricken" , "Showing remorse" .)