A professional performer rates it badly (7)
I believe the answer is:
artiste
'a professional performer' is the definition.
(I've seen this before)
'rates it badly' is the wordplay.
'badly' indicates anagramming the letters.
'rates'+'it'='ratesit'
'ratesit' anagrammed gives 'ARTISTE'.
(Other definitions for artiste that I've seen before include "Attires for professional entertainer" , "Person playing" , "Theatre performer" , "Attires like entertainer" , "Tears it (anag.)" .)