Meaning

noun a facial expression of dislike or displeasure

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

originFrom Middle English frounen (“to frown as an expression of disapproval, displeasure, shame, fear, or jealousy”), from Old French froignier, froingnier, frognier (“to wrinkle the mouth or forehead, frown, scowl”), of uncertain and disputed origin. Perhaps from Medieval Latin fruncāre (“to wrinkle, crease, turn up one's nose, make a face, frown”) (compare Old High German fruncetura (“wrinkle”), via…

Etymology from Wiktionary, CC BY-SA 3.0