Lout starts to hate officers, suffering in gaol (8)
I believe the answer is:
hooligan
'lout' is the definition.
(thesaurus)
'starts to hate officers suffering in gaol' is the wordplay.
'starts to' indicates taking the first letters.
'suffering' indicates anagramming the letters.
The initial letters of 'hate officers' is 'ho'.
'in'+'gaol'='ingaol'
'ingaol' anagrammed gives 'oligan'.
'ho'+'oligan'='HOOLIGAN'
(Other definitions for hooligan that I've seen before include "Undesirable" , "Lawless type" , "Antisocial rough" , "Ruffian, noisy troublemaker" , "Destructive or badly-behaved youth" .)