Definition of "frown"

frown¹

/fɹaʊn/

noun
plural frowns
1. A wrinkling of the forehead with the eyebrows brought together, typically indicating displeasure, severity, or concentration.
  Quotations
  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.
  Quotations
  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 December, “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)

frown²

/fɹaʊn/

verb
third-person singular simple present frowns, present participle frowning, simple past and past participle frowned
1. (intransitive) To have a frown on one's face.
2. (intransitive, figurative) To manifest displeasure or disapprobation; to look with disfavour or threateningly.
  Quotations
  The sky doth frown and lower upon our army.
  c. 1593 (date written), William Shakespeare, “The Tragedy of Richard the Third: […]”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act V, scene iii]
3. (transitive) To repress or repel by expressing displeasure or disapproval; to rebuke with a look.
4. (transitive) To communicate by frowning.
  Quotations
  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.”
  2017 June 26, Alexis Petridis, “Glastonbury 2017 verdict: Radiohead, Foo Fighters, Lorde, Stormzy and more”, in the Guardian‎