weaken vs slow up

weaken and slow up both are verbs.

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

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

weaken (verb)	slow up (verb)
become weaker	lose velocity; move more slowly
lessen the strength of	cause to proceed more slowly
reduce the level or intensity or size or scope of	become slow or slower
lessen in force or effect
destroy property or hinder normal operations