Meaning

verb set lower

verb make lower or quieter

verb look angry or sullen, wrinkle one's forehead, as if to signal disapproval

originThe verb is derived from Middle English louren, lour, loure (“to frown or scowl; to be dark or overcast; to droop, fade, wither; to lurk, skulk”), probably from Old English *lūran, *lūrian, from Proto-Germanic *lūraną (“to lie in wait, lurk”). The English word is cognate with Danish lure (“to lie in ambush; to take a nap”), Middle Dutch loeren (modern Dutch loeren (“to lurk, spy on”)), Middle Low…

Etymology from Wiktionary, CC BY-SA 3.0