"Hi, sailor!” (4)
I believe the answer is:
ahoy
'hi sailor' 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 "Hailing term at sea" , "Coastal land" , "(Nautical) hailing call" , "Hello sailor!" , "The sailor cries ''ship . . . .''" .)