to and fro
Concise Oxford English Dictionary © 2008 Oxford University Press:
to and fro/tuːəndˈfrəʊ/
▶adverb in a constant movement backwards and forwards or from side to side. ▶verb (be toing and froing) be moving to and fro.
■ vacillate between courses of action.
▶noun constant movement backwards and forwards.– derivatives
toing and froing noun.
toing and froing noun.
'to and fro' also found in these Oxford entries:

