cummer vs sister-wife

cummer

noun
  • A female companion or intimate (of another woman). 

  • The relationship of a godmother to the other godparents (godsibs or gossips), and the legal parents, of a child. 

  • Lass, the feminine equivalent of fellow. 

  • One who cums or climaxes. 

sister-wife

noun
  • In a polygamous marriage, a woman who is simultaneously the sister and co-wife of another. 

  • A woman who is simultaneously sister and wife to her spouse. 

  • A co-wife in general. 

How often have the words cummer and sister-wife occurred in a corpus of books? (source: Google Ngram Viewer )