Any medication designed to cause irritation / A source of irritation.

Causing irritation or inflammation. / (law, Scotland) Rendering null and void; conditionally invalidating.

plural of irritant

One who or that which irritates.

serving to excite or irritate / accompanied with, or produced by, increased action or irritation

Any substance causing irritation; an irritant.

The quality of being irritant or irritating. / (law, Scotland) The state or quality of being null and void; invalidity

plural of irritancy

Third-person singular simple present indicative form of irritate

plural of irritation