Definition of "darkling"

So, out went the candle, and we were left darkling.

c. 1603–1606, William Shakespeare, “The Tragedie of King Lear”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act I, scene iv]

As the wakeful bird sings darkling.

1667, John Milton, “Book III”, in Paradise Lost. […], London: […] [Samuel Simmons], […]; republished as Paradise Lost in Ten Books: […], London: Basil Montagu Pickering […], 1873,

I had a dream, which was not all a dream. / The bright sun was extinguish'd, and the stars / Did wander darkling in the eternal space, / Rayless, and pathless, and the icy earth / Swung blind and blackening in the moonless air;

1816, Lord Byron, Darkness

And we are here as on a darkling plainSwept with confused alarms of struggle and flight,Where ignorant armies clash by night

1867, Matthew Arnold, Dover Beach:

The air is cool and it’s darkling, / And calmly flows the Rhine; / The mountain tops are sparkling / In sunset’s parting shrine.

1876, Heinrich Heine, translated by Thomas Selby Egan, Atta Troll and Other Poems, London: Chapman and Hall, […], page 165

To us and to an observer about Ripley it would have had precisely the same effect the Martians seemed in solitary possession of the darkling night, lit only as it was by the slender moon, the stars, the after-glow of the daylight[.]

1898, H.G. Wells, The War of the Worlds, London: William Heinemann, page 140