go down vs diminish

go down and diminish both are verbs.

Word	Noun	Adjective	Verb	Adverb
go down	No	No	Yes	No
diminish	No	No	Yes	No

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

Other hypernyms of go down include decrease, fall, lessen.

go down (verb)	diminish (verb)
grow smaller	decrease in size, extent, or range
stop operating	lessen the authority, dignity, or reputation of
be defeated
be ingested
go under
disappear beyond the horizon
move downward and lower, but not necessarily all the way
be recorded or remembered