Goes smartly to turn back (4)
I believe the answer is:
nips
'goes' is the definition.
The answer and definition can be both acts as well as being plural nouns.
Perhaps you can see an association between them that I don't see?
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for nips that I've seen before include "Pinches as crab does" , "Squeezes tightly between the fingers" , "little drinks" , "Pinches - in the bud?" , "Tots" .)