Apparently this is an accurate description of the Universe, and the philosophical notions of Tao, but I haven't read the books yet. The word has a similar meaning to: Unsayaboutable, Unspeakaboutable, and Inconverseaboutable. The six syllables present in Untalkaboutable are said to coalesce the finite underpinnings of the Universe. Fuck, wait a second, syllables don't exist.
Student: "You just talked about Tao. Stop talking. It is untalkaboutable."
Philosophy Teacher: "Discussion presupposes that..."
Student: "SHUT UP IT IS UNTALKABOUTABLE!"