hackneyed vs commonplace

hackneyed is not a noun while commonplace is a noun.

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

As adjectives, hackneyed and commonplace are synonyms defined as:

hackneyed and commonplace: repeated too often; overfamiliar through overuse

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

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

hackneyed (adjective)	commonplace (adjective)
repeated too often; overfamiliar through overuse	not challenging; dull and lacking excitement
	repeated too often; overfamiliar through overuse
	completely ordinary and unremarkable