shopworn vs commonplace

shopworn is not a noun while commonplace is a noun.

Word	Noun	Adjective	Verb	Adverb
shopworn	No	Yes	No	No
commonplace	Yes	Yes	No	No

As adjectives, shopworn and commonplace are synonyms defined as:

shopworn and commonplace: repeated too often; overfamiliar through overuse

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

shopworn (noun)	commonplace (noun)
	a trite or obvious remark

shopworn (adjective)	commonplace (adjective)
repeated too often; overfamiliar through overuse	not challenging; dull and lacking excitement
worn or faded from being on display in a store	repeated too often; overfamiliar through overuse
	completely ordinary and unremarkable