dead-end street vs impasse

dead-end street and impasse both are nouns.

Word	Noun	Adjective	Verb	Adverb
dead-end street	Yes	No	No	No
impasse	Yes	No	No	No

As nouns, dead-end street and impasse are synonyms defined as:

Other synonyms of dead-end street include blind alley, cul de sac.

dead-end street (noun)	impasse (noun)
a street with only one way in or out	a street with only one way in or out
	a situation in which no progress can be made or no advancement is possible