ambiguity vs ambiguousness

ambiguity

noun
  • The state of being ambiguous. 

  • words or statements that are open to more than one interpretation, explanation or meaning, especially if that meaning cannot be determined from its context. 

ambiguousness

noun
  • The state or quality of being ambiguous; ambiguity 

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