noun (n)

• the act of causing something to move up and down (or back and forth) with quick movements(noun.act)

  source: wordnet30
• a shaky motion(noun.state)

  Example:
  The shaking of his fingers as he lit his pipe.
  

  Synonym:
  palpitation, quiver, quivering, shakiness, trembling, vibration
  

  source: wordnet30