ebullience vs lethargy

ebullience

noun
  • A boiling or bubbling up; an ebullition. 

  • The quality of enthusiastic or lively expression of feelings and thoughts. 

lethargy

noun
  • A condition characterized by extreme fatigue or drowsiness, deep unresponsiveness, or prolonged sleep patterns. 

  • A state of extreme torpor or apathy, especially with lack of emotion, energy or enthusiasm; (loosely) sluggishness, laziness. 

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