let up

informal

If bad weather or an unpleasant situation lets up, it stops or improves:
When the rain lets up we'll go for a walk.

to stop doing something that you have been doing continuously or in a determined way:
Neil spent the entire evening moaning about his job - he just wouldn't let up.
The police insist that they are not letting up on their campaign against drugs.

a pause or reduction in something, usually something bad:
The airline authorities are not expecting a let-up in delays (= are not expecting delays to stop) for the rest of the summer.

アメリカ英語辞典
(esp. of something unpleasant) to become less strong or stop:
When the rain lets up we’ll go for a walk.
(Cambridge Academic Content Dictionary からの let up の定義 © Cambridge University Press)

let upの例
The time scale involved-a year or so of rigorous dieting without let-up-makes failure virtually certain.
Cambridge English Corpus から
There was no let-up in the violence.
Cambridge English Corpus から

- Cambridge Dictionary