Extended opus rated badly (9)
I believe the answer is:
outspread
'extended' is the definition.
(synonyms)
'opus rated badly' is the wordplay.
'badly' indicates an anagram (letters in the wrong order).
'opus'+'rated'='opusrated'
'opusrated' is an anagram of 'OUTSPREAD'.
(Other definitions for outspread that I've seen before include "Scattered" , "Fully extended" , "Wide apart" .)