To tread water is to stay upright in deep water without moving along. Tread water for a minute.
It is the first thing taught in water safety, since it buys time to think. To tread water figuratively means keeping going without making any progress.
1phrasetread waterTo stay upright in deep water without moving along.
“He could tread water for twenty minutes without tiring.”
tread water is a phrase.
Practised in Swimming & Diving