Towards the stern of a ship (5)
I believe the answer is:
abaft
'towards the stern of a ship' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for abaft that I've seen before include "(Nautically) behind" , "Astern, at sea" , "nearer the stern" , "behind at sea" , "Towards the back (naut.)" .)