flutter vs tremble

flutter

verb
  • To flap or wave quickly but irregularly. 

  • To be in a state of agitation or uncertainty. 

  • To subject to a lie detector test. 

  • Of a winged animal: to flap the wings without flying; to fly with a light flapping of the wings. 

  • To undergo divergent oscillations (potentially to the point of causing structural failure) due to a positive feedback loop between elastic deformation and aerodynamic forces. 

  • To cause something to flap. 

  • To drive into disorder; to throw into confusion. 

noun
  • A state of agitation. 

  • The rapid variation of signal parameters, such as amplitude, phase, and frequency. 

  • A small bet or risky investment. 

  • The act of fluttering; quick and irregular motion. 

  • 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. 

  • A hasty game of cards or similar. 

  • An abnormal rapid pulsation of the heart. 

tremble

verb
  • To shake, quiver, or vibrate. 

  • To fear; to be afraid. 

noun
  • A shake, quiver, or vibration. 

How often have the words flutter and tremble occurred in a corpus of books? (source: Google Ngram Viewer )