Rogue makes refund including half of profit (9)
I believe the answer is:
reprobate
'rogue' is the definition.
(I've seen this before)
'refund including half of profit' is the wordplay.
'refund' becomes 'rebate' (rebate is a kind of refund).
'including' indicates putting letters inside.
'half of' indicates taking half.
'profit' cut in half is 'pro'.
'rebate' going around 'pro' is 'REPROBATE'.
'makes' is the link.
(Other definitions for reprobate that I've seen before include "Disapprove of" , "corrupt" , "scoundrel" , "immoral" , "Person without moral scruples" .)