Real shake-up in unit with cheat (9)

I believe the answer is:

authentic

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'real' is the definition.
(I've seen this before)

I don't understand how the rest of the clue works.

(Other definitions for authentic that I've seen before include "Ian, the cut is genuine" , "24 [LEGIT]" , "Genuine, not a copy" , "Bona fide" , "reliable" .)

I've seen this clue in The Sun.

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