I will object, taking one note to be unlawful (7)
I believe the answer is:
illicit
'be unlawful' is the definition.
(synonyms)
'i will object taking one note' is the wordplay.
'i will' becomes 'I'll' (abbreviation).
'object' becomes 'it' (pronoun for an inanimate object).
'taking' means one lot of letters goes inside another.
'one' becomes 'i' (Roman numeral).
'note' becomes 'c' (musical note).
'ill'+'it'='illit'
'i'+'c'='ic'
'illit' going around 'ic' is 'ILLICIT'.
'to' acts as a link.
(Other definitions for illicit that I've seen before include "wrong" , "Not legal" , "Contrary to or forbidden by law" , "criminal" , "Bootleg; clandestine" .)