Say nothing at work but tell the police (4)
I believe the answer is:
shop
'tell the police' is the definition.
I can't judge whether this definition defines the answer.
'say nothing at work but' is the wordplay.
'say nothing' becomes 'sh' ('sh' is said to tell someone to say nothing).
'at' means one lot of letters go next to another.
'work but' becomes 'op' (abbreviation for opus. I am not sure about the 'but' bit.).
'sh'+'op'='SHOP'
Can you help me to learn more?
(Other definitions for shop that I've seen before include "Store - workplace" , "Give away" , "Where goods are bought and sold" , "Inform on; store" , "Establishment for the sale of goods" .)