Was very much against a horrible death (5)
I believe the answer is:
hated
'was very much against' is the definition.
'a horrible death' is the wordplay.
'a horrible' indicates an anagram.
'death' anagrammed gives 'HATED'.
(Other definitions for hated that I've seen before include "gave stinking review to?" , "Loathed" , "couldn't stand" , "Detested" , "Death (anag)" .)