Sailor man reported a bit of gunpowder (9)
I believe the answer is:
saltpetre
'gunpowder' is the definition.
The answer and definition can be both substances as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
'sailor man reported a bit' is the wordplay.
'sailor' becomes 'salt' (salt is a kind of sailor).
'man' becomes 'p' (abbreviation for pawn, a chess piece or 'man').
'reported a bit' becomes 'etre' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'salt'+'p'+'etre'='SALTPETRE'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for saltpetre that I've seen before include "Nitre" , "Explosive ingredient" , "Compound" , "It's used as a fertilizer and explosive" , "Potassium nitrate" .)