Mean to follow stoat’s first trail (5)
I believe the answer is:
spoor
'trail' is the definition.
(I know that spoor is a type of trail)
'mean to follow stoat's first' is the wordplay.
'mean' becomes 'poor' (poor can mean meagre or mean).
'to follow' says to put letters next to each other (some letters go after or follow others).
'stoat's first' becomes 's' (1st letter of 'stoat').
'poor' put after 's' is 'SPOOR'.
(Other definitions for spoor that I've seen before include "Track of wild animal" , "Animal's track/scent" , "Animal track, trail" , "Beast's trail" , "Animal's track or scent" .)