Baggage fires (5)
I believe the answer is:
sacks
'fires' is the definition.
('sack' can be a synonym of 'fire')
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for sacks that I've seen before include "Plunders; fires" , "Terminates employment as punishment" , "Discharges" , "sends up in flames" , "Dismisses; bags" .)