'slow up' definitions:

Definition of 'slow up'

From: WordNet
verb
Become slow or slower; "Production slowed" [syn: slow, slow down, slow up, slack, slacken]
verb
Cause to proceed more slowly; "The illness slowed him down" [syn: slow, slow down, slow up]
verb
Lose velocity; move more slowly; "The car decelerated" [syn: decelerate, slow, slow down, slow up, retard] [ant: accelerate, quicken, speed, speed up]

Synonyms of 'slow up'

From: Moby Thesaurus