Rising stench on fish with note “past sell by date” (8)
I believe the answer is:
obsolete
'date' is the definition.
(thesaurus)
'rising stench on fish with note past sell' is the wordplay.
I cannot really see how this works, but
'fish' could be 'sole' (sole is a kind of fish) and 'sole' is found in the answer.
'note' could be 'te' (musical note) and 'te' is present in the answer.
The remaining letters 'ob' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'by' acts as a link.
Can you help me to learn more?
(Other definitions for obsolete that I've seen before include "Discontinued" , "Disused" , "Outmoded, passe" , "Out-of-date" , "being out of practice" .)