From the same as 'aphel; dusk -- darkness, obscurity, privily.
see HEBREW 'aphel
H652. ophel
אֹ֫פֶל noun masculine Job 3:6 darkness, gloom (only in poetry) -׳א always absolute —
1 darkness,, of night Psalm 91:6 (opposed to צָֽהֳרַיִם deep in the earth,א ׳אֶבֶן Job 28:3 ("" צַלְמָוֶת חשֶׁח); darkness, gloom of underworld 10:22 (twice in verse) ("" צַלְמָוֶת עֵיפָפָה׳א חשֶׁח אֶרֶץ); personified 3:6 that night — let darkness take it א ׳יִקָּחֵהוּ; figurative of spiritual darkness Isaiah 29:18 ("" חשֵׁח); of secrecy, treachery Psalm 11:2.
2 especially figurative of calamity, Job 23:17 ("" ך חשׁ q. v.), 30:26 (opposed to אוֺר ).