עֲרָפֶל
From LSJ
Πάντα ταῦτα ἐπείρασα ἐν τῇ σοφίᾳ: εἶπα Σοφισθήσομαι, καὶ αὐτὴ ἐμακρύνθη ἀπ' ἐμοῦ· κτλ. (Εcclesiastes 7:23f., LXX version) → I tried to give proof in wisdom of all those things; I said, I will be wise, but that wisdom was far from me ...
English (Strong)
probably from עָרַף; gloom (as of a lowering sky): (gross, thick) dark (cloud, -ness).