anxiety vs trepidation

anxiety

noun
  • An unpleasant state of mental uneasiness, nervousness, apprehension and obsession or concern about some uncertain event. 

  • An uneasy or distressing desire (for something). 

  • A state of restlessness and agitation, often accompanied by a distressing sense of oppression or tightness in the stomach. 

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 anxiety and trepidation occurred in a corpus of books? (source: Google Ngram Viewer )