trembler vs trembling

trembler

noun
  • One who, or that which, trembles. 

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

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

trembling

noun
  • a tremble 

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