Sister outside a church in shade (6)
I believe the answer is:
nuance
'shade' is the definition.
(I know that shade can be written as nuance)
'sister outside a church' is the wordplay.
'sister' becomes 'nun' (sister is a term of address for a nun).
'outside' means one lot of letters goes inside another.
'church' becomes 'CE' (abbreviation for Church of England).
'nun' placed around 'a' is 'nuan'.
'nuan'+'ce'='NUANCE'
'in' acts as a link.
(Other definitions for nuance that I've seen before include "Delicate shade of meaning" , "A slight shade or trace" , "Subtle shade of meaning" , "Subtlety, nicety" , "Subtle variation, in meaning say" .)