slow up

verb, noun — 2 senses

slow up

verbalso spelled slow-up

1

Colloquial, Idiomatic To slow; to slow down; to decelerate.

She has been intto prison ministry work for several years and has never slowed up, but intensified her love.1976 December 18, John Gibbs, “A True Sister”, in Gay Community News, volume 4, number 25, page 4:
Roscoe slowed up at the town limit.1997, Lee Child, “Chapter 22”, in Killing Floor:

1 more example

Amidst all the chaos, Großer Kurfürst slows up and strikes her colors, her crew having had enough, and have^([sic]) overpowered the officers - willing to fight, but not willing to commit suicide.2018 October 17, Drachinifel, 25:13 from the start, in Last Ride of the High Seas Fleet - Battle of Texel 1918, archived from the original on 04 Aug 2022:

Synonyms: slow, slow down, decelerate
Antonyms: speed up, accelerate

slow-up

noun

1

deceleration

Entry derived from the Wiktionary, under licence CC BY-SA 4.0 — authors: page histories for slow up and slow-up.