Bill supported by clergyman is correct (8)
I believe the answer is:
accurate
'is correct' is the definition.
('accurate' is associated in meaning with 'correct')
'bill supported by clergyman' is the wordplay.
'bill' becomes 'ac'.
'supported by' is a charade indicator (letters next to each other) (letters go below - in down clue).
'clergyman' becomes 'curate' (curate is a kind of clergyman).
'ac'+'curate'='ACCURATE'
(Other definitions for accurate that I've seen before include "Bang on" , "Correct in all details" , "Meticulous" , "Care a cut is exact" , "carefully and precisely" .)