acquaintance vs godsib

acquaintance

noun
  • Such people collectively; one's circle of acquaintances (with plural concord). 

  • A state of being acquainted with a person; originally indicating friendship, intimacy, but now suggesting a slight knowledge less deep than that of friendship; acquaintanceship. 

  • Personal knowledge (with a specific subject etc.). 

  • A person or persons with whom one is acquainted. 

godsib

noun
  • One's sibling or kin via a godfamily tie: one's or one's child's godparent, or one's godchild's parent, or one's godparent's child. 

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