Toward the back of a ship (3)
I believe the answer is:
aft
'toward the back of a ship' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for aft that I've seen before include "Rear part" , "Farther back on board" , "Towards rear (of ship)" , "At the back at sea" , "Near the rear (of ship)" .)