wear away vs rub off

wear away and rub off both are verbs.

Word	Noun	Adjective	Verb	Adverb
wear away	No	No	Yes	No
rub off	No	No	Yes	No

As verbs, rub off is a hyponym of wear away; that is, rub off is a word with a more specific, narrower meaning than wear away:

Other hyponyms of wear away include abrade, abrase, corrade, rub down.

wear away (verb)	rub off (verb)
become ground down or deteriorate	wear away
diminish, as by friction
cut away in small pieces