dress suit vs white tie

dress suit and white tie both are nouns.

Word	Noun	Adjective	Verb	Adverb
dress suit	Yes	No	No	No
white tie	Yes	No	No	No

As nouns, dress suit and white tie are synonyms defined as:

dress suit and white tie: formalwear consisting of full evening dress for men

Other synonyms of dress suit include full dress, tail coat, tailcoat, tails, white tie and tails.

dress suit (noun)	white tie (noun)
formalwear consisting of full evening dress for men	bow tie worn as part of a man's formal evening dress
	formalwear consisting of full evening dress for men