Very good note by Charles (6)
I believe the answer is:
chaste
'very good' is the definition.
'chaste' can be an answer for 'good' (thesaurus). I am not certain of the 'very' bit.
'note by charles' is the wordplay.
'note' becomes 'te'.
'by' says to put letters next to each other.
'charles' becomes 'chas' (shortened form).
'te' put after 'chas' is 'CHASTE'.
Can you help me to learn more?
(Other definitions for chaste that I've seen before include "sober" , "He-cats could be virtuous, strangely" , "Decorous" , "Set Cha up for being pure" , "Morally pure" .)