Blind alley (3-2-3)
'blind alley' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for cul-de-sac that I've seen before include "closed-off area" , "Street with only one way in or out" , "A street with only one entrance-exit" , "'There's only one way in and out (3,2,3)'" , "Street closed at one end" .)
'blind alley' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for dead end that I've seen before include "going nowhere" , "A blind alley, point of no further progress" , "Where no progress can be made" , "A blind alley, sounds moribund" , "Blind alley, cul-de-sac" .)