demode vs antique

demode is not a noun while antique is a noun.

Word	Noun	Adjective	Verb	Adverb
demode	No	Yes	No	No
antique	Yes	Yes	Yes	No

As adjectives, demode and antique are synonyms defined as:

Other synonyms of demode include ex, old-fashioned, old-hat, outmoded, passe, passee.

demode (noun)	antique (noun)
	any piece of furniture or decorative object or the like produced in a former period and valuable because of its beauty or rarity
	an elderly man

demode (adjective)	antique (adjective)
out of fashion	made in or typical of earlier times and valued for its age
	out of fashion
	belonging to or lasting from times long ago

demode (verb)	antique (verb)
	give an antique appearance to
	shop for antiques