Inferior not even in cast (6)
I believe the answer is:
shoddy
'inferior' is the definition.
('shoddy' can be similar in meaning to 'inferior')
'not even in cast' is the wordplay.
'not even' becomes 'odd' ('odd' is the opposite to 'even').
'in' is an insertion indicator.
'cast' becomes 'shy' (I've seen this before**).
'odd' put into 'shy' is 'SHODDY'.
(Other definitions for shoddy that I've seen before include "recycled material" , "poor quality fabric" , "inferior cloth" , "clippings in this" , "Cheap, of poor quality" .)