Affair that may be brief (4)
I believe the answer is:
case
'affair' is the definition.
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for case that I've seen before include "Piece of luggage and a lawyer's proceeding" , "Court evidence" , "A proceeding in a court of law" , "condition" , "Overnight bag" .)