Ir″ri‐tant, n. [Cf. F. irritant.]
1. That which irritates or excites.
2. (Physiol. & Med.) Any agent by which irritation is produced; as, a chemical irritant; a mechanical or electrical irritant.
3. (Toxicology) 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.