Smart uniform in shocking state (6)

I believe the answer is:

astute

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But I can't explain it at all! Could you help me understand?

(Other definitions for astute that I've seen before include "Having hardheaded intelligence" , "Clever and canny" , "Clever and crafty" , "Able to assess (people or situations) accurately" , "Canny and sagacious" .)

I've seen this clue in The Daily Mail.

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