The Collaborative International Dictionary
Tenebrous \Ten"e*brous\, a. [L. tenebrosus, fr. tenebrae darkness: cf. F. t['e]n['e]breux.] Dark; gloomy; dusky; tenebrious. -- Ten"e*brous*ness, n.
The most dark, tenebrous night.
--J. Hall
(1565).
The towering and tenebrous boughts of the cypress.
--Longfellow.
Wiktionary
n. The state or property of being tenebrous.
Usage examples of "tenebrousness".
For dark, ah, dark, is this void into which from solid ground I am now gone a trillion furlongs down, the toy of all the whirlwinds: and it would have been better for me to have deceased with the dead, and never to have seen the tenebrousness and turbulence of the ineffable, nor to have heard the thrilling bleakness of the winds of eternity, when they yearn, and plead, and whimper, and when they vociferate and blaspheme, and when they reason and intrigue and entreat, and when they despair and faint, which ear should never hear: for they mean to eat me up, I know, these vast darks, and soon like chaff I shall pass, leaving this scene to them.