Answer: slowup

AnswerCrossword Clue
SLOWUPDecelerate
SLOWUPReduce speed
SLOWUPDelay
SLOWUPPut on the brakes
SLOWUPPut on the brake.
SLOWUPDelay.
SLOWUPStep on the brakes.
SLOWUPLose speed