slow-down

(v) lose velocity; move more slowly
- The car decelerated
decelerate, slow, slow up, retard,
(v) become slow or slower
- Production slowed
slacken, slow up, slow, slack,
(v) cause to proceed more slowly
- The illness slowed him down
slow up, slow,
(v) reduce the speed of
- He slowed down the car
decelerate,
(v) become less tense, rest, or take one's ease
- He relaxed in the hot tub
- Let's all relax after a hard day's work
relax, decompress, unwind, loosen up, unbend,

decelerate slow slow up retard slacken slack relax decompress unwind loosen up unbend

accelerate quicken speed up speed tense up tense