ambiguity vs irresolution

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. 

irresolution

noun
  • Lack of resolution; lack of decision or purpose; vacillation. 

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