defecation vs diarrhea

defecation

noun
  • The act or process of voiding feces from the bowels. 

  • Any of several processes for the removal of impurities, or for clarifying various materials. 

diarrhea

noun
  • The watery or very soft excrement that comes from such bowel movements. 

  • A gastrointestinal disorder characterized by frequent and very soft or watery bowel movements. 

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