Roget's Thesaurus: Entry 426 (Opacity)

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#426. Opacity.-- N. opacity; opaqueness &c. adj. film; cloud &c. 353.

V. be opaque &c. adj.; obstruct the passage of light; obfuscate, offuscate|.

Adj. opaque, impervious to light; adiaphanous[obs]; dim &c. 422; turbid, thick, muddy, opacous|, obfuscated, fuliginous[obs], cloud, hazy, misty, foggy, vaporous, nubiferous[obs], muggy|| (turbidity) 426a.

smoky, fumid[obs], murky, dirty. #426a Turbidity -- N. turbidity, cloudiness, fog, haze, muddiness, haziness, obscurity.

nephelometer[instrument to measure turbidity].

Adj. turbid, thick, muddy, obfuscated, fuliginous[obs], hazy, misty, foggy, vaporous, nubiferous[obs]; cloudy (cloud) 353.

smoky, fumid[obs], murky, dirty.