aunt-in-law vs old woman

aunt-in-law

noun
  • The aunt of one's wife. 

  • The aunt of one's husband. 

  • The wife of one's uncle or aunt (parent's sibling). 

old woman

noun
  • One's wife. 

  • One's mother. 

  • An elderly woman. 

  • A person (irrespective of age or sex) who is always complaining about his or her situation. 

  • The plant sea wormwood. 

How often have the words aunt-in-law and old woman occurred in a corpus of books? (source: Google Ngram Viewer )