false note

Noun

false note (plural false notes)

1. An incorrect note which is sung or played in a musical performance.
   • Sometimes he even thrums a little on the piano, and takes a part in a trio, in which his voice can generally be distinguished by a certain quavering tone, and an occasional false note.1819, Washington Irving, “The Lovers”, in Bracebridge Hall
   • Her fingers wavered on the piano—she struck a false note, confused herself in trying to set it right, and dropped her hands angrily on her lap.1860, Wilkie Collins, chapter 15, in The Woman in White
2. (broadly, idiomatic) Of a remark or narrative, an indication (as discerned by the listener or reader) of untruth, insincerity, or inconsistency.
   • [H]is words were grave, his manner was earnest, and his speech came from the fulness of his heart. If there had been a false note, a false look, Harry would have detected both, […]1900, Fergus Hume, “Mr Baltic, Missionary”, in Bishop Pendle: Or, The Bishop’s Secret, Chicago, Ill.; New York, N.Y.: Rand, McNally & Company, →OCLC, page 202
   • The screenplay . . . even suggests that this contributed to the false note on which The African Queen actually ends.1990 September 14, Janet Maslin, “Movie Review: White Hunter Black Heart (1990)”, in New York Times, retrieved 16 Apr 2015
3. (broadly, idiomatic) Of a non-verbal display or presentation, an indication of incongruity or inappropriateness.
   • The only false note in an otherwise classic and elegant collection was the gratuitous flash of black fishnet stockings and suspenders under otherwise unremarkable paisley and floral shirts.2009 February 20, Hilary Alexander, “London Fashion Week: Caroline Charles”, in Telegraph, UK, retrieved 16 Apr 2015