opacity

Estimated CEFR level: C2 — Proficiency

Estimated from word frequency; not an official CEFR classification.

Definition

noun the phenomenon of not permitting the passage of electromagnetic radiation
noun incomprehensibility resulting from obscurity of meaning
noun the quality of being opaque to a degree; the degree to which something reduces the passage of light

From opaque + -ity, from French opacité, from Latin opacitas.

Who knows whether these opacities will not become transparent? — Les Misérables, Victor Hugo
Crimson opacity struggled sullenly against violet curtain of annihilation. — Triplanetary, E. E. (Edward Elmer) Smith
And under that mattress of pale opacity the tanks crawled heavily. — Astounding Stories of Super-Science January 1930, Unknown

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