nonsmoking car vs nonsmoker

nonsmoking car and nonsmoker both are nouns.

Word	Noun	Adjective	Verb	Adverb
nonsmoking car	Yes	No	No	No
nonsmoker	Yes	No	No	No

As nouns, nonsmoking car and nonsmoker are synonyms defined as:

nonsmoking car and nonsmoker: a passenger car for passengers who want to avoid tobacco smoke

nonsmoking car (noun)	nonsmoker (noun)
a passenger car for passengers who want to avoid tobacco smoke	a passenger car for passengers who want to avoid tobacco smoke
	a person who does not smoke tobacco