Behind, nautically
I believe the answer is:
abaft
'behind nautically' 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 "Towards the back (naut.)" , "In the stern half of a ship" , "behind at sea" , "(Nautically) behind" , "near end of Titanic?" .)