Bee wings in August flutter (3)
I believe the answer is:
bat
'flutter' is the definition.
('bat' can be a synonym of 'flutter')
'bee wings in august' is the wordplay.
'bee' becomes 'b'.
'wings in' suggests removing the centre (wings can mean the edges of something).
'august' with its centre removed is 'at'.
'b'+'at'='BAT'
(Other definitions for bat that I've seen before include "Creature" , "Small mammal or cricket striker" , "Cricket, table-tennis and baseball implement" , "Cricketer; mammal" , "Night-flying mammal" .)