One will depart parish and use false god (4)
I believe the answer is:
zeus
'god' is the definition.
(Zeus is an example)
'one will depart parish and use false' is the wordplay.
I cannot really see how this works, but
an anagram of 'use' is 'eus' which is within the answer.
A single letter 'z' remains which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for zeus that I've seen before include "old Greek" , "King of Greek gods" , "Greek god of gods" , "Supreme god of the ancient Greeks" , "Ancient Greek god, son of Rhea and Cronus" .)