Sailor's shout (4)
I believe the answer is:
ahoy
'sailor's shout' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ahoy that I've seen before include "A sailor's call to a ship" , "Naval call for attention" , "Nautical greeting" , "Sailor's cry to ship" , "Call for ship's attention" .)