defect vs irregularity

defect

noun
  • A fault or malfunction. 

  • A part by which a figure or quantity is wanting or deficient. 

  • The quantity or amount by which anything falls short. 

verb
  • To desert one's army, to flee from combat. 

  • To abandon or turn against; to cease or change one's loyalty, especially from a military organisation or political party. 

  • To flee one's country and seek asylum. 

  • To join the enemy army. 

irregularity

noun
  • A violation of rules. 

  • An object or event that is not regular or ordinary. 

  • An instance of being irregular. 

  • Irregular bowel movement (e.g. diarrhea or constipation). 

  • The state or condition of being irregular, or the extent to which something is irregular. 

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