What is black letter law?

Answer 1

Black letter law doesn't allow for any grey area to debate or argue. Stopping your car at a red light is an example of black letter law. You have to do it or you break the (black letter) law.

Answer 2

"Black letter law" refers to a proposition of law that is deemed to be well-established, unequivocal and irrefutable. The foregoing is academic in nature and intended for the general interest of the audience. It is NOT legal advice or opinion.