Answer briefly as before: "Bother!" (3)
I believe the answer is:
ado
'bother' is the definition.
(both can mean fuss or commotion)
'answer briefly as before' is the wordplay.
'answer briefly' becomes 'a' (abbreviation eg in Q and A; 'briefly' indicates an abbreviation).
'as before' becomes 'do' (I've seen this in other clues).
'a'+'do'='ADO'
(Other definitions for ado that I've seen before include "Hoo-ha" , "Shakespeare: 'Much ... About Nothing'(3) ()" , "Fuss, bother" , "'Much ... About Nothing, Shakespeare play (3)'" , "Busy activity, trouble" .)