Explosive cat is terribly arrogant (9)
I believe the answer is:
bombastic
'arrogant' is the definition.
Both the answer and definition are adjectives. Perhaps there's a link between them I don't understand?
'explosive cat is terribly' is the wordplay.
'explosive' becomes 'bomb' (a bomb is a type of explosive).
'terribly' is an anagram indicator.
'cat'+'is'='catis'
'catis' anagrammed gives 'astic'.
'bomb'+'astic'='BOMBASTIC'
Can you help me to learn more?
(Other definitions for bombastic that I've seen before include "Extravagant" , "Pompous -- inflated" , "High-flown" , "I cast bomb, being pompous in speech" , "affected" .)