freeway vs expressway

freeway and expressway both are nouns.

Word	Noun	Adjective	Verb	Adverb
freeway	Yes	No	No	No
expressway	Yes	No	No	No

As nouns, freeway and expressway are synonyms defined as:

Other synonyms of freeway include motorway, pike, state highway, superhighway, throughway, thruway.

freeway (noun)	expressway (noun)
a broad highway designed for high-speed traffic	a broad highway designed for high-speed traffic