fall off vs go away

fall off and go away both are verbs.

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

As verbs, go away is a hypernym of fall off; that is, go away is a word with a broader meaning than fall off:

Other hypernyms of fall off include disappear, vanish.

fall off (verb)	go away (verb)
fall heavily or suddenly; decline markedly	get lost, as without warning or explanation
diminish in size or intensity	go away from a place
come off	move away from a place into another direction
	become invisible or unnoticeable