Drunken celeb, reeling, showing hostility (12)
I believe the answer is:
belligerence
'hostility' is the definition.
(belligerence is a kind of hostility)
'drunken celeb reeling' is the wordplay.
'drunken' is an anagram indicator.
'celeb'+'reeling'='celebreeling'
'celebreeling' anagrammed gives 'BELLIGERENCE'.
'showing' acts as a link.
(Other definitions for belligerence that I've seen before include "sabre-rattling" , "Aggression" , "Pugnacity" , "Aggressive behaviour" , "Aggressiveness" .)