undescribable

But now quiet, save for an undescribable, whispering overtone that seemed to permeate the air.

My act was in some sort an act of insanity; but how undescribable are the feelings with which I looked back upon it!

That is why Plato193 says of (Unity) that it is unspeakable and undescribable.

The sins of this system are enormous and undescribable; but, thank God!

Wilfred said, with a voice utterly undescribable: "I told Norman myself to beware of the thunderbolt."