Look - a person of intelligence! (3)

I believe the answer is:

spy

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'look' is the definition.
(spy can mean to look or see)

I don't understand the rest of the clue.

(Other definitions for spy that I've seen before include "Keep watch secretly, maybe for foreign government" , "Notice" , "Mole, agent" , "Secret agent of government" , "Watch covertly like secret agent" .)

I've seen this clue in the Evening Standard.

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