What is the concept in Arabic to shut out questioning of the Koran?

What is the arabic word for shutting out any questioning of the authority or infallibility of the suras/ Koran.

There’s probably many words… boring words meaning sacred, protected, sacrosanct, unquestioinable, immutable, irreffutable and so on,

There is “I’jaz” , inimitability , which means that the written word is a miracle created by god. That changing a single word would be admitting its creation was imperfect…

The trouble is that its written in arabic, so what of other languages and language drift ?

The Prophet (as Rasul) was divinely inspired, plus he spoke Arabic, so there is not supposed to be a possibility that there was some “language drift”. Plus he was pure (tahir), ma’asum (“protected”), etc.

So the Muslim belief is Koran is the word of God (Allah) as dictated to (inspired?) and written down by the prophet? Much as the fundamentalist Christian belief is that the Bible is the word of God simply transcribed by mortals?

Nope. He was illiterate. The Qur’an was written by scribes from recitations.

So The Prophet has no idea what was actually written.

The idea (see History of the Quran - Wikipedia) is that all the verses were authenticated before being compiled. As for Muhammad, at some point (632) he died so was not around to triple-check any final final canonical version.

One legend about The Prophet is that when he was first visited by the angel Gabriel he was commanded to recite some material out loud, and the latter became increasingly frustrated when it turned out Muhammad could not read.