Pressure exerted on behalf of the church (5)
I believe the answer is:
force
'pressure' is the definition.
(I know that pressure can be written as force)
'on behalf of the church' is the wordplay.
'on behalf of' becomes 'for' (eg speaking on behalf of or for someone else).
'the church' becomes 'CE' (Church of England).
'for'+'ce'='FORCE'
'exerted' acts as a link.
This may not be correct. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for force that I've seen before include "Lean on" , "Dynamism" , "Compulsion - police" , "Might" , "'Compel, pressurise (5)'" .)