What do آپ think the Deplorable Word is?

Good question, Lewis was not a descriptive writer and drew a lot from myth. The deplorable word mite be the same as Lilith speaking the unspeakable name of god and for doing so she was turned into a demon. Jadis is a descended of Lilith probably her daughter and is also a demon and not a witch. I think the price she paid to learn it was she lost her immortality when she spoke it and had to put herself in to a trance to survive but regained it when she ate one of Aslans apples. The word is so powerful it can destroy whole worlds for when Jadis left Charn it was destroyed and in the Magician's Nephew when Aslan was creating Narnia it is کہا that "she would have smashed that whole world, یا all worlds, to pieces". Jadis could not use the word in Narnia as she was trapped there with no means of escape the rings were buried in London and the wardrobe was made from the same wood as the درخت that kept her out of Narnia for a 1000 years.