go down vs lower

go down is not a noun while lower is a noun.

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

go down (noun)	lower (noun)
	the lower of two berths

go down (adjective)	lower (adjective)
	the bottom one of two

go down (verb)	lower (verb)
grow smaller	make lower or quieter
stop operating	set lower
be defeated	cause to drop or sink
be ingested	move something or somebody to a lower position
go under	look angry or sullen, wrinkle one's forehead, as if to signal disapproval
disappear beyond the horizon
move downward and lower, but not necessarily all the way
be recorded or remembered