Posh headgear of birds out for a bit of fun (6)
I believe the answer is:
'for a bit of fun' is the definition.
I can't tell whether this definition defines the answer.
'posh headgear of birds out' is the wordplay.
'posh headgear of' becomes 'n' (I can't explain this - if you can you should believe this answer much more).
'birds' becomes 'crows' (crow is a kind of bird).
'out' indicates putting letters inside.
'n' placed within 'crows' is 'CROWNS'.
Can you help me to learn more?
(Other definitions for crowns that I've seen before include "caps" , "At least ten shillings" , "emblems of kingship" , "Tops of heads - tops of teeth" , "Symbols of monarchy" .)