Rubbish not even collected by cast (6)
I believe the answer is:
shoddy
'rubbish' is the definition.
(thesaurus)
'not even collected by cast' is the wordplay.
'not even' becomes 'odd' ('odd' is the opposite to 'even').
'collected by' indicates putting letters inside.
'cast' becomes 'shy' (I've seen this before).
'odd' going inside 'shy' is 'SHODDY'.
(Other definitions for shoddy that I've seen before include "Cheap and inferior" , "Of inferior workmanship" , "Gimcrack" , "Badly done; recycled fibre" , "Cheap and poorly made" .)