Droppings from small animal (4)
I believe the answer is:
scat
'droppings' is the definition.
(scat can mean the droppings of an animal)
'small animal' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'animal' becomes 'cat' (I've seen this in other clues).
's'+'cat'='SCAT'
'from' acts as a link.
(Other definitions for scat that I've seen before include "Animal droppings - small silvery fish" , "Shoo!" , "Buzz off" , "Bolt" , "improvisation in jazz" .)