tremble vs trembler

tremble

noun
  • A shake, quiver, or vibration. 

verb
  • To shake, quiver, or vibrate. 

  • To fear; to be afraid. 

trembler

noun
  • The vibrating hammer, or spring contact piece of a hammer break, as of the electric ignition apparatus for an internal combustion engine. 

  • One who, or that which, trembles. 

  • Any of various New World passerine birds of the family Mimidae. 

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