Cut work on Sunday inside law establishment (7)
I believe the answer is:
copshop
'cut work on sunday' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.
'law establishment' is the wordplay.
'law' becomes 'cop' (I am not sure about this - if you are sure you should believe this answer much more).
'establishment' becomes 'shop' (shop is a kind of establishment).
'cop'+'shop'='COPSHOP'
'inside' acts as a link.
Can you help me to learn more?
(Other definitions for copshop that I've seen before include "police station" , "bluebottle, buzzing in this?" .)