Possibly unwelcome review of books? (5)

I believe the answer is:

audit

I'm a little stuck... Click here to teach me more about this clue!

'review of books?' is the definition.
(I've seen this before)

I cannot understand how the remainder of the clue works.

(Other definitions for audit that I've seen before include "HMRC inspection" , "Go over" , "Financial review" , "Official inspection of company accounts" , "Conduct annual check of firm's accounts" .)

I've seen this clue in The Sun.

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