The man's transgression finding answer in sackcloth? (7)
I believe the answer is:
hessian
'sackcloth?' is the definition.
(I've seen this before)
'the man's transgression finding answer in' is the wordplay.
'the man' becomes 'hes' (I've seen this in other clues).
'transgression' becomes 'sin' (sin is a kind of transgression).
'finding' says to put letters next to each other.
'answer' becomes 'a' (abbreviation eg in Q and A).
'in' means one lot of letters goes inside another.
'hes'+'sin'='hessin'
'hessin' placed around 'a' is 'HESSIAN'.
(Other definitions for hessian that I've seen before include "sackcloth?" , "Coarse fabric used in sacks" , "Cloth for sacking" , "Coarse jute fabric" , "Jute clothing" .)