Smashing reply: it's divine (8)
I believe the answer is:
priestly
'divine' is the definition.
Both the definition and answer are adjectives. Perhaps you can see an association between them that I can't see?
'smashing reply it's' is the wordplay.
'smashing' is an anagram indicator.
'reply'+'its'='replyits'
'replyits' is an anagram of 'PRIESTLY'.
Can you help me to learn more?
(Other definitions for priestly that I've seen before include "Pious" , "Ecclesiastical" , "just like a cleric" , "Hieratic" , "Like a minister" .)