Sailor selling freight caught on board A1 Greek ship (10)
I believe the answer is:
supercargo
'sailor' is the definition.
(I know that supercargo is a type of officer)
'greek ship' is the wordplay.
'greek' becomes 'super' (I can't explain this - if you can you should give a lot more credence to this answer).
'ship' becomes 'cargo ship' (cargo ship is a kind of ship).
'super'+'cargo'='SUPERCARGO'
'selling freight caught on board a1' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for supercargo that I've seen before include "Ship's officer" , "Merchant navy officer responsible for what a ship is carrying" , "Owner's representative on merchant ship" .)