Headgear with fashionable insert, reversed flap (5)
I believe the answer is:
panic
'flap' is the definition.
(I've seen this in another clue)
'headgear with fashionable insert reversed' is the wordplay.
'headgear' becomes 'cap' (cap is a kind of headgear).
'with fashionable' becomes 'in' (in can mean fashionable or trendy. I am not sure about the 'with' bit.).
'insert' is an insertion indicator.
'reversed' is a reversal indicator.
'cap' enclosing 'in' is 'cinap'.
'cinap' written backwards gives 'PANIC'.
Can you help me to learn more?
(Other definitions for panic that I've seen before include "Alarm - terror" , "Horror" , "Have kittens" , "Greek god" , "Take fright, lose the head" .)