Break, as a rule (7)
I believe the answer is:
violate
'break as a rule' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for violate that I've seen before include "Contravene" , "Transgress" , "Treat with great disrespect" , "Desecrate, despoil" , "Abuse" .)