Business rated incorrectly (5)
I believe the answer is:
trade
'business' is the definition.
(I know that trade is a type of business)
'rated incorrectly' is the wordplay.
'incorrectly' indicates an anagram (I've seen this in other clues).
'rated' with letters rearranged gives 'TRADE'.
(Other definitions for trade that I've seen before include "groundsman?" , "Dealings, business" , "Rated (anag.)" , "Buying/selling of goods" , "Barter, do business" .)