opacity

Noun

1. The state or quality of being opaque, not allowing light to pass through.
   • We could not see the sandbar due to the opacity of the muddy water.

   Synonyms: opaqueness nontransparency

   Antonyms: clarity clearness translucency transparency

2. The state or quality of being inaccessible to understanding.
   • The opacity of these decisions is troubling.

   Antonyms: clarity lucidity

3. A measure of relative impenetrability to electromagnetic radiation such as light.
   • The opacity of a clean glass window is near zero.
4. An opaque area.
   • This report concerns a child with Down's syndrome (mongolism) and bilateral congenital corneal opacities born into a family affected through three generations by Rieger's anomaly. - 1968, Dark A. J., Kirkham T. H.,...
   • Scanty irregular opacities are not uncommonly observed on the chest roentgenogram in the absence of interstitial fibrosis of the lungs. - 1992, Dick, J. A. et al., “The significance of irregular opacities on the chest...