No-nonsense detective abandoning precinct (6)

I believe the answer is:

strict

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'no-nonsense' is the definition.
(I've seen this before)

I don't understand the remainder of the clue.

(Other definitions for strict that I've seen before include "Allowing no laxness" , "Rigidly enforced" , "Allowing no deviation from a standard" , "Observing exact rules" , "Stringent" .)

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