Advertise scent (5)
I believe the answer is:
trail
This clue is a double definition.
'advertise' is the first definition.
(I've seen this before)
'scent' is the second definition.
(I've seen this before)
(Other definitions for trail that I've seen before include "Track made through wild country" , "Drag behind" , "Drop behind" , "Straggle" , "Get behind" .)