Defy female hoodlum (5)
I believe the answer is:
flout
'defy' is the definition.
(I've seen this before)
'female hoodlum' is the wordplay.
'female' becomes 'f' (common abbreviation).
'hoodlum' becomes 'lout' (both can mean a violent youth).
'f'+'lout'='FLOUT'
(Other definitions for flout that I've seen before include "Treat with disdain" , "Defy (orders etc)" , "Ignore (rule)" , "Show contempt for (the law)" , "Treat with contempt" .)