। ॥ १७ ॥
In plain words
Whatever appears wearing the stamp of 'this' — all of it gets negated. What remains is the Reality no word can touch: not a 'this' at all, never an object you could know, because it shines by its own light.
Close to the Sanskrit
Whatever shines only as 'this-ness' — all that is negated; and the inexpressible Reality, being not-this, is not to be known, because of self-luminosity.