Definition of "flutter"
flutter
/ˈflʌtə/
verb
third-person singular simple present flutters, present participle fluttering, simple past and past participle fluttered
(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.
noun
countable and uncountable, plural flutters