to and fro

adverb

Pronunciation: /ˌtuː ən(d)ˈfɹəʊ/

Pertaining to something or someone moving forward and back to the same position.
“The next day he had more power of moving his limbs, and the to and fro sound was thought to be a little less distinct.”

Back and forth; with a reciprocating motion.
“A light tossing to and fro and still rapidly advancing showed that one of the newcomers carried a lantern.”
“Article V.—In consideration of the numerous difficulties arising from the authority exercised by local officials over the legal traffic at such places on the boundary as I-chou, Hui-ning, and Ch’ing-yuan, it has now been decided that the people on the frontier shall be free to go to and fro and trade as they please at Ts’e-men and I-chou on the two sides of the Ya-lu River, and at Hun-ch’un and Hui-ning on the two sides of the T’u-men River.”

The movement (of someone or something) forward followed by a return to the same position. May refer to a concept such as an emotional state or a relationship as well as a physical thing.
“My life's a maze of seeming traps, A scene of mercies and mishaps; A heap of jarring to and fros, A field of joys, A field of woes.”

To go back and forth; to alternate.
“"For a while I didn't tell anyone on the ward where I was going, but my toing and froing made people curious and eventually I confided in a few."”