impasse vs dead-end street

impasse and dead-end street both are nouns.

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

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

Other synonyms of impasse include blind alley, cul de sac.

impasse (noun)	dead-end street (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