Verify said money order (6)
I believe the answer is:
cheque
'money order' is the definition.
(thesaurus)
'verify said' is the wordplay.
'verify' becomes 'check' (checking is a kind of verifying).
'said' indicates a 'sounds like' (homophone) clue.
'check' is a homophone of 'CHEQUE'.
(Other definitions for cheque that I've seen before include "Bank document" , "Written order directing a bank to pay money" , "Means of payment" , "Written document authorising payment to recipient" , "Signed money order" .)