wearing away vs eating away

wearing away and eating away both are nouns.

Word	Noun	Adjective	Verb	Adverb
wearing away	Yes	No	No	No
eating away	Yes	No	No	No

As nouns, wearing away and eating away are synonyms defined as:

wearing away and eating away: (geology) the mechanical process of wearing or grinding something down (as by particles washing over it), also figuratively

Other synonyms of wearing away include eroding, erosion, wearing.

wearing away (noun)	eating away (noun)
(geology) the mechanical process of wearing or grinding something down (as by particles washing over it), also figuratively	(geology) the mechanical process of wearing or grinding something down (as by particles washing over it), also figuratively