Act of contrition in Cornish location - character at the end released (7)
I believe the answer is:
penance
'act of contrition' is the definition.
(as in doing penance)
'cornish location character at the end released' is the wordplay.
'cornish location' becomes 'Penzance' (Penzance is a town in Cornwall).
'character at the end' becomes 'z' (letter at the end of the alphabet).
'released' is a deletion indicator.
'penzance' with 'z' taken out is 'PENANCE'.
'in' acts as a link.
(Other definitions for penance that I've seen before include "Punishment inflicted on oneself" , "act of expiation" , "Punishment imposed for sin" , "Hardship" , "Remorse" .)