airhead vs vernacular

airhead and vernacular both are nouns.

Word	Noun	Adjective	Verb	Adverb
airhead	Yes	No	No	No
vernacular	Yes	Yes	No	No

airhead (noun)	vernacular (noun)
a bridgehead seized by airborne troops	the everyday speech of the people (as distinguished from literary language)
a flighty scatterbrained simpleton	a characteristic language of a particular group (as among thieves)

airhead (adjective)	vernacular (adjective)
	being or characteristic of or appropriate to everyday language