Copper arresting drunk in a flap (5)
I believe the answer is:
panic
'flap' is the definition.
(I've seen this before)
'copper arresting drunk in a' is the wordplay.
'copper' becomes 'pc' (**).
'arresting' means one lot of letters goes inside another.
'drunk' is an anagram indicator.
'in'+'a'='ina'
'ina' anagrammed gives 'ani'.
'pc' going around 'ani' is 'PANIC'.
(Other definitions for panic that I've seen before include "Sudden overpowering anxiety" , "Frantic fear" , "Widespread fear" , "Alarm - terror" , "Agitation" .)