definition of
[blind alley]

[1] #1 blind alley n. a street with only one way in or out. wn

[2] #2 blind alley n. (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". wn