Catholic to have another look at his belief (5)
I believe the answer is:
credo
'his belief' is the definition.
'credo' can be an answer for 'belief' (credo is a kind of belief). I am not sure about the 'his' bit.
'catholic to have another look' is the wordplay.
'catholic' becomes 'c' (abbreviation as in RC for Roman Catholic).
'to have' says to put letters next to each other.
'another look' becomes 'redo' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'c'+'redo'='CREDO'
'at' is the link.
Can you help me to learn more?
(Other definitions for credo that I've seen before include "Section of mass" , "ideology" , "Decor (anag.)" , "Formal statement of beliefs" , "Words of believer" .)