white tie vs eveningwear

white tie and eveningwear both are nouns.

Word	Noun	Adjective	Verb	Adverb
white tie	Yes	No	No	No
eveningwear	Yes	No	No	No

As nouns, eveningwear is a hypernym of white tie; that is, eveningwear is a word with a broader meaning than white tie:

Other hypernyms of white tie include evening clothes, evening dress, formalwear.

white tie (noun)	eveningwear (noun)
bow tie worn as part of a man's formal evening dress	attire to wear on formal occasions in the evening
formalwear consisting of full evening dress for men