abnormality vs tendency

abnormality

noun
  • The state or quality of being abnormal; variation; irregularity. 

  • Something abnormal; an aberration; an abnormal occurrence or feature. 

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. 

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