darkling
Dark; growing dark; darkening.
She still pursued its flight, with all the speed / Her fainting strength had hitherto supplied: / What pathless wilds she crossed ! What forests darkling wide !
Obscure; taking place unseen, as if in the dark.
figuratively
Where it comes from
Coined by Irish poet Mary Tighe in 1805, likely as an extension of the adverbial sense, and popularized by John Keats.
Adapted from the Wiktionary entry darkling (CC BY-SA 4.0).