commonplace vs banal

commonplace is a noun but banal is not a noun.

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

As adjectives, commonplace and banal are synonyms defined as:

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

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

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