subside vs go under

subside and go under both are verbs.

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

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

Other hypernyms of subside include go down, settle, sink.

subside (verb)	go under (verb)
wear off or die down	be called; go by a certain name
sink down or precipitate	go under
sink to a lower level or form a depression	disappear beyond the horizon
descend into or as if into some soft substance or place