gnaw vs wear away

gnaw and wear away both are verbs.

Word	Noun	Adjective	Verb	Adverb
gnaw	No	No	Yes	No
wear away	No	No	Yes	No

As verbs, gnaw and wear away are synonyms defined as:

Other synonyms of gnaw include eat at, erode, gnaw at.

gnaw (verb)	wear away (verb)
become ground down or deteriorate	become ground down or deteriorate
bite or chew on with the teeth	diminish, as by friction
	cut away in small pieces