Definition of "irritant"

irritant

/ˈɪɹɪtənt/

adjective
not comparable
1. Causing irritation or inflammation.
2. (law, Scotland) Rendering null and void; conditionally invalidating.
  Quotations
  The states elected Harry, Duke of Anjou, for their king, with this clause irritant; that, if he did violate any part of his oath, the people should owe him no allegiance.
  1603, Hayward, An Answer to the first part of a certaine conference concerning succession
noun
plural irritants
1. Any medication designed to cause irritation
2. A source of irritation.