IRRITANT
irritant, thorn
(noun) something that causes irritation and annoyance; “he’s a thorn in my flesh”
Source: WordNet® 3.1
Etymology
Adjective
irritant (not comparable)
Causing irritation or inflammation.
(legal, Scotland) Rendering null and void; conditionally invalidating.
Noun
irritant (plural irritants)
Any medication designed to cause irritation
A source of irritation.
Source: Wiktionary
Ir"ri*tant, a. Etym: [LL. irritants, -antis, p. pr. of irritare to
make null, fr. L. irritus void; pref. ir- not + ratus established.]
(Scots Law)
Definition: 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.
Ir"ri*tant, a. Etym: [L. irritans, -antis, p. pr. of irritare: cf. F.
irritant. See Irritate to excite.]
Definition: Irritating; producing irritation or inflammation.
Ir"ri*tant, n. Etym: [Cf. F. irritant.]
1. That which irritates or excites.
2. (Physiol. & Med.)
Definition: Any agent by which irritation is produced; as, a chemical
irritant; a mechanical or electrical irritant.
3. (Toxicology)
Definition: 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.
Source: Webster’s Unabridged Dictionary 1913 Edition