opacity

1. The state or quality of being opaque, not allowing light to pass through. (uncountable) · We could not see the sandbar due to the opacity of the muddy water.
2. The state or quality of being inaccessible to understanding. (uncountable) · The opacity of these decisions is troubling.
3. A measure of relative impenetrability to electromagnetic radiation such as light. (countable) · The opacity of a clean glass window is near zero.
4. An opaque area. (countable)

الجمع opacities