irrefrangible

irrefrangible \ir-i-FRAN-juh-buhl\, adjective:

1. not to be broken or violated; inviolable: an irrefrangible rule of etiquette.
2. incapable of being refracted.

In any other nation a typical official like Eliav would find himself allied against the priests who insisted upon such irrefrangible law, and even he had begun to echo the warning voiced by liana Hacohen: "this Mickey Mouse crap."
-- James A. Michener, The Source

But no, Kipling never forgets that Kim is an irrefrangible part of British India: the Great Game does go on, with Kim a part of it, no matter how many parables the lama fashions.
-- Rudyard Kipling, Edward W. Said, "Introduction," Kim

This Baroque era word irrefrangible derives from a negation of the Latin root frangere meaning "to break," also the root of the word "fraction."