go down vs let down

go down and let down both are verbs.

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

go down (verb)	let down (verb)
grow smaller	fail to meet the hopes or expectations of
stop operating	move something or somebody to a lower position
be defeated
be ingested
go under
disappear beyond the horizon
move downward and lower, but not necessarily all the way
be recorded or remembered