Hoodwink flapper (4)
I believe the answer is:
gull
I believe this clue is a double definition.
'hoodwink' is the first definition.
(thesaurus)
'flapper' is the second definition.
(a gull flaps its wings)
(Other definitions for gull that I've seen before include "Fool - hoax" , "A bird; to deceive" , "Dupe - sea bird" , "Seabird with a raucous call" , "Rook - bird of the sea" .)