Possibly calumnious, nothing less, to describe a composer thus? (9)
I believe the answer is:
unmusical
'describe a composer thus?' is the definition.
I can't judge whether this defines the answer.
'possibly calumnious nothing less' is the wordplay.
'possibly' indicates anagramming the letters.
'nothing' becomes 'o' (looks like zero - 0).
'less' is a deletion indicator.
'calumnious' with 'o' removed is 'calumnius'.
'calumnius' with letters rearranged gives 'UNMUSICAL'.
'to' acts as a link.
Can you help me to learn more?
(Another definition for unmusical that I've seen is " not appreciating many of these answers?".)