Against the clock means hurrying to finish before time runs out. Working against the clock.
The deadline is the opponent, which is what the against is doing. In sport it also means timed individually rather than raced side by side.
1phraseagainst the clockHurrying to finish before time runs out.
“The whole crew worked against the clock to get the roof on.”
against the clock is a phrase.
Practised in Idioms