Monster like Radovan Karadžic sounding certain to make a comeback (8)
I believe the answer is:
cerberus
'monster' is the definition.
(I know that Cerberus is a type of mythical creature)
'like radovan karadzic sounding certain to make a comeback' is the wordplay.
'like radovan karadzic' becomes 'Serb' (Radovan Karadic is a Serbian politician).
'sounding' shows a homophone (sound like).
'certain' becomes 'sure' (synonyms).
'to make a comeback' says the letters should be written backwards (I've seen 'making a comeback' mean this).
'serb' sounds like 'cerb'.
'sure' reversed gives 'erus'.
'cerb'+'erus'='CERBERUS'
(Other definitions for cerberus that I've seen before include "Three-headed guard dog" , "Mythical three-headed watchdog guarding Hades" , "Three-headed dog guarding entrance to Hades" , "Underground watchdog" , "Three headed guard dog of Hades" .)