wear down vs wear thin

wear down and wear thin both are verbs.

Word	Noun	Adjective	Verb	Adverb
wear down	No	No	Yes	No
wear thin	No	No	Yes	No

As verbs, wear down and wear thin are synonyms defined as:

Other synonyms of wear down include wear, wear off, wear out.

wear down (verb)	wear thin (verb)
exhaust or get tired through overuse or great strain or stress	deteriorate through use or stress
deteriorate through use or stress