dead end vs impasse

dead end and impasse both are nouns.

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

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

dead end and impasse: a situation in which no progress can be made or no advancement is possible

Other synonyms of dead end include deadlock, stalemate, standstill.

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