Yob (4)
'yob' is the definition.
(both can mean an antisocial young man)
This is all the clue.
(Other definitions for lout that I've seen before include "A noisy badly-behaved fellow" , "Lob" , "Yobbo" , "Ill-mannered youth" , "disrespectful person" .)
(Other definitions for hoodlum that I've seen before include "Small-time gangster" , "Aggressive young criminal" , "Hooligan" , "Petty ruffian" , "American thug" .)