scowl (v.)

"lower the brows, as in anger or displeasure, put on a frowning look," c. 1400, scoulen, probably from a Scandinavian source (compare Norwegian skule "look furtively, squint, look embarrassed," Danish skule "to scowl, cast down the eyes"). According to Klein's sources, this is probably related to Old English sceolh "wry, oblique," Old High German scelah "curved," German scheel "squint-eyed;" from a PIE root *sqel- "crooked, curved, bent." Related: Scowled; scowling; scowlingly.

"a lowering or wrinkling of the brows, as in anger or displeasure; a malevolent, lowering look," c. 1500, from scowl (v.).