The snag in quoting bits from the catechism (5)
I believe the answer is:
catch
'the snag' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for catch that I've seen before include "a sort of 22" , "Something trapped" , "Accurately detect" , "Ensnare" , "Desirable partner" .)