unpredictability vs weakness

unpredictability

noun
  • The quality of being unpredictable. 

  • Something which is unpredictable. 

weakness

noun
  • An inadequate quality; fault 

  • The condition of being weak. 

  • A special fondness or desire. 

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