wear upon vs wear down

wear upon and wear down both are verbs.

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

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

wear upon and wear down: exhaust or get tired through overuse or great strain or stress

Other synonyms of wear upon include fag, fag out, fatigue, jade, outwear, tire, tire out, wear, wear out, weary.

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