Definition of "flutter" in English

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.

noun

1. The act of fluttering; quick and irregular motion.

   • the flutter of a fan

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.

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.

5. (British) A small bet or risky investment.

   • 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.