decelerate
verb [ I or T ] uk/ˌdiːˈsel.ər.eɪt/ us/ˌdiːˈsel.ə.reɪt/
（使）降低速度;（使）减速
to reduce the speed that a vehicle is travelling at
The car decelerated at the sight of the police car. 那辆汽车一见警车就慢了下来。
（使）减缓发生
to happen or make something happen more slowly
Compare: accelerate