slow up vs slow down

slow up and slow down both are verbs.

Word	Noun	Adjective	Verb	Adverb
slow up	No	No	Yes	No
slow down	No	No	Yes	No

As verbs, slow up and slow down are synonyms defined as:

Other synonyms of slow up include decelerate, retard, slow.

As verbs, slow down is a hyponym of slow up; that is, slow down is a word with a more specific, narrower meaning than slow up:

Other hyponyms of slow up include slow, slow up, delay, detain, hold up.

As verbs, slow up and slow down are synonyms defined as:

Other synonyms of slow up include slow.

As verbs, slow down is a hypernym of slow up; that is, slow down is a word with a broader meaning than slow up:

Other hypernyms of slow up include decelerate, retard, slow, slow up.

As verbs, slow up and slow down are synonyms defined as:

Other synonyms of slow up include slack, slacken, slow.

slow up (verb)	slow down (verb)
lose velocity; move more slowly	become less tense, rest, or take one's ease
cause to proceed more slowly	lose velocity; move more slowly
become slow or slower	become slow or slower
	reduce the speed of
	cause to proceed more slowly