abnormal vs unnatural

abnormal

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

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

noun
  • A person or object that is not normal. 

unnatural

adj
  • Not natural. 

  • Going against nature; perverse. 

  • Not occurring in nature, the environment or atmosphere 

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