(uncountable) The state or characteristic of being indescribable.
1992, H. M. Vroom, "Can Religious Experience Be Shared?," in On Sharing Religious Experience ed. by J. D. Gort et al., Eerdmans Publishing, ISBN 0802805051, p. 7,This emphasis on the indescribability of God in intense religious experience is consistently found in the more mystical religious traditions.
1843, Thomas_Carlyle, Past and Present, ch. 2,The clothed embodied justice that sits in Westminster Hall, with penalties, parchments, tipstaves, is very visible. But the unembodied justice, whereof that other is either an emblem, or else is a fearful indescribability, is not so visible!