Renoir if badly composed is second-rate (8)
I believe the answer is:
inferior
'second-rate' is the definition.
(similar in meaning)
'renoir if badly composed' is the wordplay.
'badly composed' indicates anagramming the letters.
'renoir'+'if'='renoirif'
'renoirif' is an anagram of 'INFERIOR'.
'is' is the link.
(Other definitions for inferior that I've seen before include "Less good" , "strictly for the birds" , "Poorer in quality" , "Of poor quality" , "Substandard, lower in quality" .)