dinner jacket vs formalwear

dinner jacket and formalwear both are nouns.

Word	Noun	Adjective	Verb	Adverb
dinner jacket	Yes	No	No	No
formalwear	Yes	No	No	No

As nouns, formalwear is a hypernym of dinner jacket; that is, formalwear is a word with a broader meaning than dinner jacket:

Other hypernyms of dinner jacket include evening clothes, evening dress, eveningwear.

dinner jacket (noun)	formalwear (noun)
semiformal evening dress for men	attire to wear on formal occasions in the evening