Tracking first scoundrel on foot (7)
I believe the answer is:
trotter
'on foot' is the definition.
(I know that inception subproperty of point in time)
'tracking first scoundrel' is the wordplay.
'tracking first' becomes 't' (1st letter of 'tracking').
'scoundrel' becomes 'rotter' (both can mean a nasty person).
't'+'rotter'='TROTTER'
(Other definitions for trotter that I've seen before include "Food for man" , "horse getting sulky, say" , "bit of a swine" , "Edible foot?" , "foot of animal for food" .)