I may be wrong but a law forbidding a law seems to be just nonsense. Are you sure you have phrased the question properly.
To forbid = asar (אסר)
forbid (verb) = asar (אסר)
khas vekhalilah (חס וחלילה)
illegal
Canon Law does not forbid priests from participating in politics (eg: voting) but does forbid them from running for political office.
veto; Latin for "I forbid it"Which originates from the Roman Tribune's ability to forbid a law from passinghttp://en.wikipedia.org/wiki/Veto
The law of Ghalas forbid women from making canoes or weapons in Island of the Blue Dolphins. This law was intended to prevent women from hunting and fishing, which were considered tasks only for men in the society of the novel.
Veto
oser (אוסר) is the present tense masculine singular form of the verb asar (אסר) = "to forbid".
Law = Chok (חוק)
Canon law is there specifically to regulate the dress of clerics, not laymen.
If you are asking what the Hebrew word for the Five Books of Moses is, it's the Torah (תורה). If you are asking what the Hebrew word is for the phrase "the law", it's ha-khok (החוק)