flutter

Etymology

From Middle English floteren, from Old English floterian, flotorian (“to float about, flutter”), from Proto-Germanic *flutrōną, frequentative of Proto-Germanic *flutōną (“to float”), equivalent to float + -er (frequentative suffix). Cognate with Low German fluttern, fluddern (“to flutter”), German flittern, Dutch fladderen; also Albanian flutur (“butterfly”). More at float.

verb

1. (intransitive) To flap or wave quickly but irregularly.
   flags fluttering in the wind
2. (intransitive) Of a winged animal: to flap the wings without flying; to fly with a light flapping of the wings.
3. (intransitive, aerodynamics) To undergo divergent oscillations (potentially to the point of causing structural failure) due to a positive feedback loop between elastic deformation and aerodynamic forces.
4. (transitive) To cause something to flap.
   A bird flutters its wings.
5. (transitive) To drive into disorder; to throw into confusion.
6. (intransitive) To be in a state of agitation or uncertainty.
7. (intransitive, obsolete) To be frivolous.
8. (espionage, slang) To subject to a lie detector test.
   This was the first time that Nosenko had been subjected to a lie detector — or what the CIA called fluttering. The Soviet Union did not use such devices for interrogation. 1978, Edward Jay Epstein, Legend: The Secret World of Lee Harvey Oswald, page 38
   "Anyway, she cracked and we fluttered her and—" / "Fluttered her?" / "Sorry, gave her a polygraph, a lie detector test. And she passed, more or less, […] 2002, Paul Eddy, Flint’s Law, page 90

noun

1. The act of fluttering; quick and irregular motion.
   the flutter of a fan
   the chirp and flutter of some single bird c. 1838, Richard Monckton Milnes, The Forest
2. A state of agitation.
   Their visitor was an issue - at least to the imagination, and they arrived finally, under provocation, at intensities of flutter in which they felt themselves so compromised by his hoverings that they could only consider with relief the fact of nobody's knowing. 1900, Henry James, The Soft Side The Third Person Chapter 3
3. An abnormal rapid pulsation of the heart.
4. (uncountable, aerodynamics) An extremely dangerous divergent oscillation caused by a positive feedback loop between the elastic deformation of an object and the aerodynamic forces acting on it, potentially resulting in rapid structural failure.
   The possibility was studied that there might be some unknown phenomenon at work that could cause a reduction in structural stiffness with age. Such a reduction in stiffness could result in a reduced flutter speed and lead to flutter. In 2004, Airbus conducted GVT in support of its MRTT program. The testing was conducted on an aged A310 aircraft (MSN 523) that had accumulated over 28 000 flight hours. This test aircraft had the same design of VTP and rudder as the occurrence aircraft. GVT results found that fin bending and rudder rotation frequencies of the MRTT test aircraft were consistent with those obtained during the original A310-300 certification. No indication was found to suggest that stiffness had reduced with age. 2007, Transportation Safety Board of Canada, “1.12.12 Age-Related Structures and Materials Degradation”, in Aviation Investigation Report A05F0047, Loss of Rudder in Flight, Air Transat Airbus A310-308 C-GPAT, Miami, Florida, 90 nm S, 06 March 2005, archived from the original on 2021-07-23, page 40
5. (Britain) A small bet or risky investment.
   "Oh, by the way, I heard of a rather good thing today, New Kleinfonteins; it's a gold mine in Rhodesia. If you'd like to have a flutter you might make a bit." 1915, W. Somerset Maugham, chapter 93, in Of Human Bondage
   30 July, 2009, Eurosport, Gray Matter: How will Schu do? So with his victory odds currently at 14/1 or 3/1 for the podium, he's still most certainly well worth a flutter […]
6. A hasty game of cards or similar.
7. (audio, electronics) The rapid variation of signal parameters, such as amplitude, phase, and frequency.
   Coordinate term: wow