Sea gull (4)
I believe the answer is:
tern
'sea gull' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tern that I've seen before include "Pay rent for seabird" , "Seabird related to the gull" , "Winger" , "Gull-like seabird" , "Fork-tailed seabird" .)