opacousness en · NOUN
Etymology
From opacous + -ness.
Meanings
-
(obsolete, uncountable) Opacity.
[T]hat 'tis the flaws that produce this opacousness, may be argued from this, that particles of the same Ammel much thicker if unflaw'd will appear somewhat transparent even to the eye […].
1665, Robert Hooke, Micrographia, section X: