Anything no good for official use (6)
I believe the answer is:
refuse
'anything no' is the definition.
The definition and answer can be both substances as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'official use' is the wordplay.
'official' becomes 'ref' (match official in football, say).
'ref'+'use'='REFUSE'
'good for' acts as a link.
Can you help me to learn more?
(Other definitions for refuse that I've seen before include "deadwood" , "Decline, repudiate" , "Turn down - rubbish" , "Decline to accept - rubbish" , "Decline to take the rubbish" .)