A struggle to maintain faith (4,3)
I believe the answer is:
holy war
'faith' is the definition.
Both the definition and answer are singular nouns.
Perhaps they are linked in a way I don't understand?
'a struggle to maintain' is the wordplay.
'a struggle' becomes 'war' (I've seen this in another clue).
'to' is a charade indicator (letters next to each other) (I've seen this in other clues).
'maintain' becomes 'holy' (I can't explain this - if you can you should believe this answer much more).
'war' after 'holy' is 'HOLY WAR'.
Can you help me to learn more?
(Other definitions for holy war that I've seen before include "Jihad" , "Religious conflict" .)