Most of religious community let down disciple (8)
I believe the answer is:
follower
'disciple' is the definition.
(I've seen this before)
'most of religious community let down' is the wordplay.
'most of religious community' becomes 'fol' (I can't explain this - if you can you should give a lot more credence to this answer).
'let down' becomes 'lower' (synonyms).
'fol'+'lower'='FOLLOWER'
Can you help me to learn more?
(Other definitions for follower that I've seen before include "One accepts the leadership of another" , "fan" , "Supporter" , "Disciple" , "A devotee or a pursuer" .)