murk

From Middle English merke, mirke, from Old English mirce, myrce (“dark, gloomy, evil”) and Old Norse myrkr (“dark, murky”), both from Proto-Germanic merkuz (“dark”), from Proto-Indo-European mergʷ- (“to flicker; to darken; to be dark”). Cognate Danish mørk (“dark”), Norwegian mørk (“dark”), Swedish mörk (“dark”), Icelandic myrkur (“dark”), as also Albanian murg (“dark”), Proto-Slavic *morkъ (“darkness”), Lithuanian márgas (“multicolored”), murzinas (“dirty, spoiled”), Ancient Greek ἀμορβός (amorbós, “dark”).

From Middle English mirke, merke, from Old English mirce, myrce (“darkness, gloom”) and Old Norse myrkr (“darkness, gloom”), both from Proto-Germanic merkwą, mirkwiz (“darkness”), Proto-Indo-European *mergʷ- (“to flicker; to darken; to be dark”).

From Middle English mirken, probably from Old Norse myrkja, myrkva (“to make dark, darken”), from Proto-Germanic mirkwijaną, mirkwajaną (“to make dark”), from Proto-Indo-European *mergʷ- (“to flicker; to darken; to be dark”).

Possibly an alteration of merc, from clipping of mercenary. First attested in the 1990s.