See something pinned up (6)

I believe the answer is:

notice

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'see' is the definition.
(notice can mean to see or realise)

I don't understand the remainder of the clue.

(Other definitions for notice that I've seen before include "Observe; advertisement" , "This is usually given before quitting job" , "Information of future events" , "See; advert" , "'Perceive, observe (6)'" .)

I've seen this clue in the Evening Standard.

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