authoritative vs unsure

authoritative

adj
  • Having a commanding style. 

  • Arising or originating from a figure of authority 

  • Highly accurate or definitive; treated or worthy of treatment as a scholarly authority 

unsure

adj
  • uncertain 

  • unstable or precarious 

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