go away vs fall away

go away and fall away both are verbs.

Word	Noun	Adjective	Verb	Adverb
go away	No	No	Yes	No
fall away	No	No	Yes	No

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

go away (verb)	fall away (verb)
get lost, as without warning or explanation	fall to a lower standard
go away from a place	diminish in size or intensity
move away from a place into another direction
become invisible or unnoticeable