slow up vs diminish

slow up and diminish both are verbs.

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

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

Other hypernyms of slow up include decrease, fall, lessen.

slow up (verb)	diminish (verb)
lose velocity; move more slowly	decrease in size, extent, or range
cause to proceed more slowly	lessen the authority, dignity, or reputation of
become slow or slower