Supporters in a whirl, perhaps, if not all of a flutter? (4)
I believe the answer is:
fans
'supporters' is the definition.
(I know this)
'a whirl perhaps if not all of a flutter?' is the wordplay.
I cannot really see how this works, but
'a' could be 'an' and 'an' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
'in' is the link.
Can you help me to learn more?
(Other definitions for fans that I've seen before include "Supporters" , "Aficionados" , "Admirers" , "Devotees" , "Provokes" .)