abnormal vs subnormal

abnormal

noun
  • A person or object that is not normal. 

adj
  • Of or pertaining to that which is irregular, in particular, behaviour that deviates from norms of social propriety or accepted standards of mental health. 

  • Not conforming to rule or system; deviating from the usual or normal type. 

subnormal

noun
  • A person whose abilities are less than normal. 

  • That part of the axis of a curved line which is intercepted between the ordinate and the normal. 

adj
  • denormal 

  • Less than normal. 

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