About fifty wrongly accused in blind alley (3-2-3)
I believe the answer is:
cul-de-sac
'blind alley' is the definition.
(I've seen this before)
'about fifty wrongly accused' is the wordplay.
'about' indicates putting letters inside.
'fifty' becomes 'L' (Roman numeral).
'wrongly' is an anagram indicator (I've seen this in other clues).
'accused' anagrammed gives 'cudesac'.
'l' going into 'cudesac' is 'CUL-DE-SAC'.
'in' is the link.
(Other definitions for cul-de-sac that I've seen before include "A street with only one entrance-exit" , "Blind alley" , "Dead-end street" , "Street closed at one end" , "Street with only one way in or out" .)