Castle gutted after catastrophic fire raging (6)
I believe the answer is:
fierce
'raging' is the definition.
(thesaurus)
'castle gutted after catastrophic fire' is the wordplay.
'gutted' suggests removing the centre (to gut something is to remove its insides).
'after' says to put letters next to each other.
'catastrophic' indicates an anagram.
'castle' with its middle taken out is 'ce'.
'fire' anagrammed gives 'fier'.
'ce' after 'fier' is 'FIERCE'.
(Other definitions for fierce that I've seen before include "Wild and savage" , "Barbarous" , "Violent in temper or manner" , "Savagely vehement" , "Menacingly wild" .)