One-time hoodlums regularly fleeing (6)
I believe the answer is:
exodus
'one-time hoodlums regularly fleeing' is the definition.
I can't judge whether this defines the answer.
'one-time hoodlums regularly fleeing' is the wordplay.
'one-time' becomes 'ex' (prefix meaning former or onetime).
'regularly fleeing' indicates alternate letters (letters removed at regular intervals).
The alternate letters of 'hoodlums' are 'odus'.
'ex'+'odus'='EXODUS'
Can you help me to learn more?
(Other definitions for exodus that I've seen before include "OT book - flight" , "A great departure or dispersal" , "Used ox (anag)" , "Second book of OT" , "a mass departure as in Bible Book" .)