Flower changes into law-breaking (9)
I believe the answer is:
violation
'law-breaking' is the definition.
(violation is a kind of law-breaking)
'flower changes into' is the wordplay.
'flower' becomes 'viola' (I've seen this before).
'changes' indicates anagramming the letters.
'into' is an anagram of 'tion'.
'viola'+'tion'='VIOLATION'
(Other definitions for violation that I've seen before include "Infringement" , "Offence" , "Breach" , "abuse" , "outrage" .)