Affair of bag (4)
I believe the answer is:
case
I believe this clue is a double definition.
'affair' is the first definition.
'bag' is the second definition.
(I know that bag is a more specific form of pack)
'of' acts as a link.
(Other definitions for case that I've seen before include "proceedings" , "Reconnoitre" , "condition" , "Patient - luggage" , "Police investigation" .)