get down vs let down

get down and let down both are verbs.

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

As verbs, get down and let down are synonyms defined as:

Other synonyms of get down include bring down, lower, take down.

get down (verb)	let down (verb)
take the first step or steps in carrying out an action	fail to meet the hopes or expectations of
put down in writing; of texts, musical compositions, etc.	move something or somebody to a lower position
pass through the esophagus as part of eating or drinking
lower someone's spirits; make downhearted
move something or somebody to a lower position
alight from (a horse)
lower (one's body) as by kneeling