Prevent fellow in congregation giving way to Bishop (5)
I believe the answer is:
block
'prevent fellow in congregation' is the definition.
'block' can be an answer for 'prevent' (blocking is a kind of preventing). I am not sure about the 'fellow in congregation' bit.
'way to bishop' is the wordplay.
'way' becomes 'lock' (I can't justify this - if you can you should believe this answer much more).
'to' says to put letters next to each other (I've seen this in other clues).
'bishop' becomes 'B' (abbreviation for bishop in chess).
'lock' after 'b' is 'BLOCK'.
'giving' acts as a link.
Can you help me to learn more?
(Other definitions for block that I've seen before include "Mass of wood etc - set of buildings" , "cake?" , "Impede, prevent" , "Solid shape; prevent" , "City area; prevent flow" .)