Against a new note? (4)
I believe the answer is:
anti
'against' is the definition.
(I've seen this before)
'a new note?' is the wordplay.
'a new' becomes 'an' (I've seen this in other clues).
'note?' becomes 'ti' (I've seen this in other clues**).
'an'+'ti'='ANTI'
(Other definitions for anti that I've seen before include "'No' voter" , "An opponent - opposed to party policy, etc" , "one opposing?" , "Naysayer" , "Hostile" .)