frown

Etymology 1

From Middle English frown, froun (“a threatening appearance; lowering of the clouds”), from frounen (“to frown”). See below.

noun

1. A wrinkling of the forehead with the eyebrows brought together, typically indicating displeasure, severity, or concentration.
   Philip had once told him of a man who had a horse-shoe frown, and Tom had tried with all his frowning-might to make a horse-shoe on his forehead 1860, George Eliot, “V: Maggie's Second Visit”, in The Mill on the Floss, Volume I Book II, Edinburgh, London: William Blackwood, page 336‑337
   He encounters some obstacle in his train of reasoning ... and then a frown passes like a shadow over his brow. 1873, Charles Darwin, The Expression of the Emotions in Man and Animals, page 223
2. (Canada, US) A downturn of the corners of the mouth, typically expressing sadness.
   The smile and the frown are both indicated and the operation of a motor driven flasher causes the face to look happy and sad in turn. 1911-12, “Facial Expression Electric Sign”, in Popular Electricity, volume iv, number 8, Chicago, page 714
   1931, “Turn That Frown Upside Down, Smile at the Cock-eyed World”, Joe Young (lyrics), Sam Stept (music):

Etymology 2

From Middle English frounen (“to frown as an expression of disapproval, displeasure, shame, fear, or jealousy”), from Old French frognier (“to frown or scowl”), from Gaulish *frognā (“nostril”), from Proto-Celtic *srognā.

verb

1. (intransitive) To have a frown on one's face.
   She frowned when I told her the news.
2. (intransitive, figurative) To manifest displeasure or disapprobation; to look with disfavour or threateningly.
   Noisy gossip in the library is frowned upon.
3. (transitive) To repress or repel by expressing displeasure or disapproval; to rebuke with a look.
   Let us frown the impudent fellow into silence.
4. (transitive) To communicate by frowning.
   Frank frowned his displeasure with my proposal.
   As the band paused between songs, a gust of wind blew a distinctive Worthy Farm odour in the direction of drummer/vocalist Julien Ehrich: “Wow,” he frowned, “this place smells of cow shit.” June 26, 2017, Alexis Petridis, “Glastonbury 2017 verdict: Radiohead, Foo Fighters, Lorde, Stormzy and more”, in the Guardian