Check-up before noon, first folder (9)

I believe the answer is:

origamist

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'folder' is the definition.
Both the answer and definition are singular nouns.
Perhaps they are linked in a way I don't understand?

'check-up before noon first' is the wordplay.
'check' becomes 'giro' (giro is a kind of check).
'up' shows that the letters should be reversed in order (in down clue: letters go upwards).
'before noon' becomes 'AM' (as in AM on a clock).
'first' becomes 'ist' (ist resembles gst).
'giro' back-to-front is 'orig'.
'orig'+'am'+'ist'='ORIGAMIST'

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I've seen this clue in The Guardian.

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