Irritant

Part of speech: noun (n.)

1. That which irritates or excites.

2. Any agent by which irritation is produced; as, a chemical irritant; a mechanical or electrical irritant.

3. A poison that produces inflammation. Counter irritant. See under Counter. -- Pure irritant (Toxicology), a poison that produces inflammation without any corrosive action upon the tissues.

Part of speech: adjective (a.)

Rendering null and void; conditionally invalidating. 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. Hayward.

Part of speech: adjective (a.)

Irritating; producing irritation or inflammation.