go under vs settle

go under is not a noun while settle is a noun.

Word	Noun	Adjective	Verb	Adverb
go under	No	No	Yes	No
settle	Yes	No	Yes	No

As verbs, go under and settle are synonyms defined as:

Other synonyms of go under include go down, sink.

As verbs, settle is a hyponym of go under; that is, settle is a word with a more specific, narrower meaning than go under:

Other hyponyms of go under include subside, founder, submerge, submerse.

go under (noun)	settle (noun)
	a long wooden bench with a back

go under (verb)	settle (verb)
be called; go by a certain name	take up residence and become established
go under	form a community
disappear beyond the horizon	become settled or established and stable in one's residence or life style
	establish or develop as a residence
	make final; put the last touches on; put into final form
	become resolved, fixed, established, or quiet
	come as if by falling
	bring to an end; settle conclusively
	settle conclusively; come to terms
	end a legal dispute by arriving at a settlement
	come to terms
	accept despite lack of complete satisfaction
	get one's revenge for a wrong or an injury
	fix firmly
	arrange or fix in the desired order
	come to rest
	settle into a position, usually on a surface or ground
	cause to become clear by forming a sediment (of liquids)
	sink down or precipitate
	go under
	become clear by the sinking of particles
	dispose of; make a financial settlement