Deal rated incorrectly (5)
I believe the answer is:
trade
'deal' is the definition.
(I know that deal is a kind of deal)
'rated incorrectly' is the wordplay.
'incorrectly' is an anagram indicator (I've seen this in other clues).
'rated' is an anagram of 'TRADE'.
(Other definitions for trade that I've seen before include "Skilled occupation" , "Barter, do business" , "Barter or swap" , "Customers" , "Deal - occupation" .)