Isn't it arch working for the enemy? (10)
I believe the answer is:
antichrist
'the enemy?' is the definition.
Both the answer and definition are singular nouns.
Maybe you can see an association between them that I don't see?
'isn't it arch working' is the wordplay.
'working' indicates an anagram.
'isnt'+'it'+'arch'='isntitarch'
'isntitarch' anagrammed gives 'ANTICHRIST'.
'for' is the link.
Can you help me to learn more?
(Other definitions for antichrist that I've seen before include "Opponent of Jesus" , "religious foe" .)