well-worn vs commonplace

well-worn is not a noun while commonplace is a noun.

Word	Noun	Adjective	Verb	Adverb
well-worn	No	Yes	No	No
commonplace	Yes	Yes	No	No

As adjectives, well-worn and commonplace are synonyms defined as:

well-worn and commonplace: repeated too often; overfamiliar through overuse

Other synonyms of well-worn include banal, hackneyed, old-hat, shopworn, stock, threadbare, timeworn, tired, trite.

well-worn (noun)	commonplace (noun)
	a trite or obvious remark

well-worn (adjective)	commonplace (adjective)
repeated too often; overfamiliar through overuse	not challenging; dull and lacking excitement
showing signs of much wear or use	repeated too often; overfamiliar through overuse
	completely ordinary and unremarkable