tendency vs weakness

tendency

noun
  • A likelihood of behaving in a particular way or going in a particular direction; a tending toward. 

  • An organised unit or faction within a larger political organisation. 

weakness

noun
  • A special fondness or desire. 

  • An inadequate quality; fault 

  • The condition of being weak. 

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