Shattering blow - no book refund! Great! (9)
I believe the answer is:
wonderful
'great' is the definition.
(both can mean amazing or grand)
'shattering blow no book refund' is the wordplay.
'shattering' indicates an anagram.
'no' indicates named letters should be taken away.
'book' becomes 'b' (abbreviation for book).
'blow' with 'b' taken out is 'low'.
'low'+'refund'='lowrefund'
'lowrefund' is an anagram of 'WONDERFUL'.
(Other definitions for wonderful that I've seen before include "Superb" , "Extraordinary" , "Fab" , "Remarkably good" , "Excellent" .)