Cod I ordered that’s only about second-rate (8)
I believe the answer is:
mediocre
'second-rate' is the definition.
(I know that second-rate can be written as mediocre)
'cod i ordered that's only about' is the wordplay.
'ordered' is an anagram indicator.
'that's only' becomes 'mere' (I've seen this in another clue).
'about' means one lot of letters goes inside another.
'cod'+'i'='codi'
'codi' with letters rearranged gives 'dioc'.
'dioc' put into 'mere' is 'MEDIOCRE'.
(Other definitions for mediocre that I've seen before include "poor to middling" , "Fair, middle of the road" , "Pedestrian, second-rate" , "Moderate to inferior in quality" , "Commonplace, not distinguished" .)