Subtlety shown by religious person describing a church (6)
I believe the answer is:
nuance
'subtlety' is the definition.
(I know that subtlety can be written as nuance)
'religious person describing a church' is the wordplay.
'religious person' becomes 'nun' (nun is a kind of religious person).
'describing' means one lot of letters goes inside another (describe can mean to form the outline of).
'church' becomes 'CE' (Church of England).
'nun' placed around 'a' is 'nuan'.
'nuan'+'ce'='NUANCE'
'shown by' acts as a link.
(Other definitions for nuance that I've seen before include "Cue Ann into slight shade" , "Ace nun (anag)" , "A hint or shade" , "Subtle distinction or variation" , "Fine distinction" .)