aggravation vs irritant

aggravation

noun
  • Provocation, irritation, annoyance. 

  • An extrinsic circumstance or accident which increases the guilt of a crime or the misery of a calamity. 

  • The act of aggravating, or making worse; used of evils, natural or moral; the act of increasing in severity or heinousness; something additional to a crime or wrong and enhancing its guilt or injurious consequences. 

  • Exaggerated representation. 

irritant

noun
  • A source of irritation. 

  • Any medication designed to cause irritation 

adj
  • Causing irritation or inflammation. 

  • Rendering null and void; conditionally invalidating. 

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