Belief about colour in French church (8)
I believe the answer is:
credence
'belief' is the definition.
(I've seen this before)
'about colour in french church' is the wordplay.
'about' becomes 'c' (abbreviation for 'circa'**).
'colour' becomes 'red' (red is a kind of colour).
'in french' becomes 'en' ('en' can be French for 'in' e.g. en France).
'church' becomes 'ce' (abbreviation for Church of England).
'c'+'red'+'en'+'ce'='CREDENCE'
(Other definitions for credence that I've seen before include "Trust" , "Sort of table" , "that creates confidence" , "Faith or belief placed in something" , "Belief in something's truth" .)