equanimity vs trepidation

equanimity

noun
  • The state of being calm, stable and composed, especially under stress. 

trepidation

noun
  • A fearful state; a state of concern or hesitation. 

  • An involuntary trembling, sometimes an effect of paralysis, but usually caused by terror or fear. 

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