Ge-sweorc

According to the Old English Dictionary:

-sworc, es;

ge-sweorc

n. [sweorcan to darken] A cloud, mist, smoke; nūbes, nĕbŭla, cālīgo :-- Gif hér wind cymþ gesweorc upfæreþ if wind comes here a cloud ascends, Cd. 38; Th. 50, 12; Gen. 807. Cining geseah deorc gesweorc the king saw a dark cloud, 5; Th. 7, 19; Gen. 108. [O. Sax. gi-swerk: O. H. Ger. gi-swerc.] ge-sweorc