to an inexpressible degree; "she was looking very young tonight, and, as usual, indescribably beautiful, in a simple strapless dress of a green and white silky cotton"
Yet to my horror I saw in its eaten-away and bone-revealing outlines a leering, abhorrent travesty on the human shape; and in its mouldy, disintegrating apparel an unspeakable quality that chilled me even more.
exceptionally bad or displeasing; "atrocious taste"; "abominable workmanship"; "an awful voice"; "dreadful manners"; "a painful performance"; "terrible handwriting"; "an unspeakable odor came sweeping into the room"
emphasis If you describe something as unspeakable, you are emphasizing that it is extremely unpleasant. the unspeakable horrors of chemical weapons unspeakable crimes. = appalling + unspeakably un·speak·ably The novel was unspeakably boring