go by vs go under

go by and go under both are verbs.

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

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

go by (verb)	go under (verb)
be or act in accordance with	be called; go by a certain name
be called; go by a certain name	go under
for time to move forward	disappear beyond the horizon
move past