antonym vs nullity

antonym

noun
  • A word which has the opposite meaning of another word. 

  • A word that describes one end of a scale, while its opposite describes the other end, such as large versus small; a gradable antonym. 

nullity

noun
  • The difference between the rank of a matrix and the number of columns it has; the dimension of the nullspace of a matrix. 

  • A void act; a defective proceeding or one expressly declared by statute to be a nullity. 

  • The state of being null, or void, or invalid. 

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