Past wrong supported by church (5)
I believe the answer is:
since
'past' is the definition.
(I've seen this before)
'wrong supported by church' is the wordplay.
'wrong' becomes 'sin' (wrong can mean a sin or crime).
'supported by' means one lot of letters go next to another (in a down clue, some letters hold up others).
'church' becomes 'ce' (Church of England).
'sin'+'ce'='SINCE'
(Other definitions for since that I've seen before include "Seeing that" , "Because; ago" , "From that time one" , "in the past" .)