dress suit vs white tie and tails

dress suit and white tie and tails both are nouns.

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

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

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

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

dress suit (noun)	white tie and tails (noun)
formalwear consisting of full evening dress for men	formalwear consisting of full evening dress for men