excretion vs voiding

excretion

noun
  • Something excreted in that manner, especially urine or feces. 

  • The process of removing or ejecting material that has no further utility, especially from the body; the act of excreting. 

voiding

noun
  • An act by which something is voided, such as urination. 

  • That which is voided; that which is ejected or evacuated; a remnant; a fragment. 

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