Intend to restrict large source of continuing religious gloom (10)
I believe the answer is:
melancholy
'gloom' is the definition.
(I've seen this before)
'intend to restrict large source of continuing religious' is the wordplay.
'intend' becomes 'mean' (meaning is a kind of intending).
'to restrict' means one lot of letters goes inside another (inserted letters are restricted or trapped).
'large' becomes 'L' (eg in clothes sizes).
'source of continuing religious' becomes 'choly' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'mean' placed around 'l' is 'melan'.
'melan'+'choly'='MELANCHOLY'
Can you help me to learn more?
(Other definitions for melancholy that I've seen before include "Depressed" , "[ODE] subject" , "Sad - tendency to depression" , "sombre" , "Sadness, gloom" .)