Junior officer’s quarters good for stopping crime (6)

I believe the answer is:

ensign

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'junior officer's' is the definition.
'ensign' can be an answer for 'officer's' (I've seen this before). I am not sure about the 'junior' bit.

'quarters good for stopping crime' is the wordplay.
'quarters' becomes 'en'.
'good' becomes 'g' (abbreviation).
'for stopping' is an insertion indicator (stopping can mean blocking a gap).
'crime' becomes 'sin'.
'g' going into 'sin' is 'sign'.
'en'+'sign'='ENSIGN'

Can you help me to learn more?

(Other definitions for ensign that I've seen before include "Flag; rank" , "US naval rank" , "Flag indicating allegiance" , "National flag" , "Soldier; standard" .)

I've seen this clue in The Times.

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