Webster’s Revised Unabridged Dictionary · 1913
Darkling
Dark′ling (därk′lĭng), adv. [Dark + the adverbial suffix -ling.] In the dark. [Poetic]
So, out went the candle, and we were left darkling. Shak.
As the wakeful bird Sings darkling. Milton.
Dark′ling, p. pr. & a. 1. Becoming dark or gloomy; frowing.
His honest brows darkling as he looked towards me. Thackeray.
2. Dark; gloomy. "The darkling precipice." Moore.