I must stop one girl reforming faith (8)
I believe the answer is:
religion
'faith' is the definition.
(I know that faith can be written as religion)
'i must stop one girl reforming' is the wordplay.
I cannot really see how this works, but
'i' is present in the answer.
'one' could be 'i' (Roman numeral) and 'i' is found in the answer.
'stop' could be 'go' (going is a kind of stopping) and 'go' is found in the leftover letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for religion that I've seen before include "Belief - way of life of monks and nuns" , "Belief in and worship of god or gods" , "System of belief or worship" , "Institution for worship" , "Organised system of faith" .)