Hither and thither (2,3,3)
I believe the answer is:
to and fro
'hither and thither' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for to and fro that I've seen before include "From place to place" , "both ways" , "Shuttle's motion" , "Backwards and forwards" , "Directions of oscillation" .)