1. a street with only one way in or out • Syn: cul de sac, dead-end street, impasse • Hypernyms: thoroughfare 2.(figurative) a course of action that is unproductive and offers no hope of improvement - all the clues led the police into blind alleys - so far every road that we've been down has turned out to be a blind alley • Usage Domain: trope, figure of speech, figure, image • Hypernyms: course, course of action