slip away vs go by

slip away and go by both are verbs.

Word	Noun	Adjective	Verb	Adverb
slip away	No	No	Yes	No
go by	No	No	Yes	No

As verbs, slip away and go by are synonyms defined as:

Other synonyms of slip away include elapse, glide by, go along, lapse, pass, slide by, slip by.

slip away (verb)	go by (verb)
for time to move forward	be or act in accordance with
leave furtively and stealthily	be called; go by a certain name
	for time to move forward
	move past