graceful dive (4)
I believe the answer is:
swan
'graceful dive' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for swan that I've seen before include "Bird of Cygnus genus" , "The Ugly Duckling's outcome" , "Whooper or trumpeter?" , "Graceful bird" , "Kind of song, in the end" .)