formalwear vs eveningwear

formalwear and eveningwear both are nouns.

Word	Noun	Adjective	Verb	Adverb
formalwear	Yes	No	No	No
eveningwear	Yes	No	No	No

As nouns, formalwear and eveningwear are synonyms defined as:

formalwear and eveningwear: attire to wear on formal occasions in the evening

Other synonyms of formalwear include evening clothes, evening dress.

formalwear (noun)	eveningwear (noun)
attire to wear on formal occasions in the evening	attire to wear on formal occasions in the evening