Probably from araph; gloom (as of a lowering sky) -- (gross, thick) dark (cloud, -ness).
see HEBREW araph
H6205. araphel
עֲרָפֶל noun masculine cloud, heavy cloud (perhaps from above √ + ל afformative; Late Hebrew = Biblical Hebrew; Syriac ; עֲרָפֵילָא ᵑ7; Mandean ארפילא NöM 126, 128; on vocaliz. see BaNB 160 and against him SchwZAW x (1890), 178 who proposes עַרְמֶּל); — ׳ע in which God dwells Exodus 20:18 (Gi; van d. H. 20:21), 1 Kings 8:12 2 Chronicles 6:1; + עָנָן Deuteronomy 4:11 (also חשֶׁח), 5:19; Psalm 97:2; Job 22:13 see בַּעַד; ׳ע רַגְלָיו תַּחַת 2 Samuel 22:10 = Psalm 18:10; as swaddling-bands of sea Job 38:9; figurative of misery Isaiah 60:2 ("" חשֶׁח); of ׳יs judgment Jeremiah 13:16 ("" צַלְמָוֶת), as a past day וַע עָנָן ׳יוֺם Ezekiel 34:12 = (of future day of ׳י) Zephaniah 1:15 ("" וַאֲפֵלָה חשֶׁח יוֺם) = Joel 2:2 ("" id.).