opacity

The sombre vision of nature's secret laws is interdicted to man by the fatal opacity of surrounding things.

The first possesses the greatest opacity, while the second and third are most durable.

Anatomical changes took place in the cornea, as evidenced by a white opacity.

The blue sky is more beautiful because we know it is not painted opacity, but transparent.

It may be she was not very visible; the double glasses of an open sash-window are almost equal to opacity.