Go in halo to sort out ruffian (8)
I believe the answer is:
hooligan
'ruffian' is the definition.
('hooligan' can be a synonym of 'ruffian')
'go in halo to sort out' is the wordplay.
'to sort out' indicates an anagram.
'go'+'in'+'halo'='goinhalo'
'goinhalo' is an anagram of 'HOOLIGAN'.
(Other definitions for hooligan that I've seen before include "Young rough" , "Lawless type" , "Destructive or badly-behaved youth" , "Ruffian, yob" , "Thug, ruffian" .)