Matey's greeting (4)
I believe the answer is:
ahoy
'matey's greeting' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ahoy that I've seen before include "(Nautical) hailing call" , "Hail at sea" , "Coastal land" , "Sailor's shout for attention" , "Naval call for attention" .)