Fraud itself must incorporate check (5)
I believe the answer is:
audit
'check' is the definition.
(I've seen this before)
'fraud itself must incorporate' is the wordplay.
'must incorporate' indicates a hidden word (the answer is incorporated in the clue).
'AUDIT' can be found hidden inside 'fraud itself'.
(Other definitions for audit that I've seen before include "Examine account" , "Financial inspection" , "HMRC inspection" , "Official inspection of company accounts" , "review of books" .)