tremor vs unconcern

tremor

noun
  • An earthquake. 

  • A shake, quiver, or vibration. 

  • A rhythmic, uncontrollable shaking of all or part of the body due to partial muscle contractions. 

verb
  • To shake or quiver excessively and rapidly or involuntarily; to tremble. 

unconcern

noun
  • Lack of interest or care; indifference or apathy. 

  • Freedom from worry or apprehensiveness; insouciance or nonchalance. 

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