Go to and fro (4)
I believe the answer is:
sway
'go to and fro' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for sway that I've seen before include "Ways to waver in opinion or posture" , "Bend; influence" , "Rock, stagger" , "Pitch sideways" , "Control" .)