Shout from ships (4)
I believe the answer is:
ahoy
'shout from ships' 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 "What a sailor may" , "Call for attention at sea" , "Mariner's call" , "Sailor's shout to ship" , "Call for ship's attention" .)