Young horse scratching a short tail (6)
I believe the answer is:
follow
'tail' is the definition.
(thesaurus)
'young horse scratching a short' is the wordplay.
I cannot quite see how this works, but
'short' could be 'low' (associated in meaning) and 'low' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for follow that I've seen before include "Succeed; go after" , "dog" , "Ensue" , "Go behind" , "Trail" .)