Small stony trail (5)
I believe the answer is:
spoor
'trail' is the definition.
(I know that spoor is a type of trail)
'small stony' is the wordplay.
I cannot quite see how this works, but
'small' could be 's' (abbreviation - e.g. clothes size) and 's' is present in the answer.
The remaining letters 'poor' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for spoor that I've seen before include "Animal track or scent" , "Track of wild animal" , "Animal track, trail" , "Animal's track/scent" , "Animal's track or scent" .)