Some complicit youth in large town (4)
I believe the answer is:
city
'large town' is the definition.
(a city is a large settlement)
'some complicit youth in' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'CITY' is hidden in the letters of 'complicit youth in'.
(Other definitions for city that I've seen before include "See 5" , "Coventry, say" , "See 9" , "Manchester, e.g." , "Important town" .)