What it means
つ〜つ describes two contrasting or complementary actions that alternate repeatedly, often conveying movement or behavior that goes back and forth. It is formed with the masu-stem of a verb followed by つ, then another masu-stem followed by つ, commonly followed by する. The expression is literary and is especially frequent in descriptions of repeated physical movement, hesitation, or changing states.
Usage note
つ〜つ is mainly used in formal or written narration and often pairs verbs with opposite or contrasting meanings, such as 行きつ戻りつ. Do not confuse it with つつ, which expresses an accompanying action or concession.
How to use it
彼は廊下を行きつ戻りつしています。
He is going back and forth along the hallway.
彼は廊下を行きつ戻りつしている。
He is going back and forth along the hallway.
Example sentences
台風の進路を示す地図を見ながら、研究者は窓辺を行きつ戻りつしていた。
While looking at a map showing the typhoon's course, the researcher paced back and forth by the window.
一枚の枯れ葉が池の水面で浮きつ沈みつしている。
A fallen leaf is repeatedly floating and sinking on the surface of the pond.