Byron regularly berates discontented ruffians (4)
I believe the answer is:
yobs
'ruffians' is the definition.
('yob' can be a synonym of 'ruffian')
'byron regularly berates discontented' is the wordplay.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
'discontented' means to remove the middle letters (the word's contents are removed).
'berates' with its centre removed is 'bs'.
The alternating letters of 'byron' are 'yo'.
'yo'+'bs'='YOBS'
(Other definitions for yobs that I've seen before include "aggressive teenagers" , "Boys who are hooligans" , "Louts" .)