irritant

1 of 2

noun

ir·​ri·​tant ˈir-ə-tənt 

: something that irritates or excites

irritant

2 of 2

adjective

: causing irritation

specifically : tending to produce physical irritation

Synonyms of irritant

Noun

• headache
• nuisance
• thorn
• frustration
• annoyance

Examples of irritant in a Sentence

Noun

dust and other lung irritants

The delay was a minor irritant.

Recent Examples on the Web

Noun

Allergy season brings airborne irritants, which include tree, grass, and ragweed pollen that trigger immune responses, which cause increased swelling. —Matthew Kayser, USA Today, 25 Mar. 2026

With its large display, single-button operation and three-color LED air quality indicator, this monitor offers a simple way to take a look at what irritants may be floating around you. —Bestreviews, Chicago Tribune, 17 Mar. 2026

Adjective

The fire department said Wednesday that the chemical released into the air was pepper spray, which is less concentrated than bear mace and creates a smaller irritant cloud. —Lucy Hodgman, San Francisco Chronicle, 11 Mar. 2026

Dark red markings on a gray panel, meanwhile, typically indicate that the ammunition contains an irritant or riot-control agent. —Bojan Stojkovski, Interesting Engineering, 8 Mar. 2026

Word History

First Known Use

Noun

1802, in the meaning defined above

Adjective

1636, in the meaning defined above

Kids Definition

irritant

1 of 2 adjective

ir·​ri·​tant ˈir-ə-tənt 

: tending to produce anger, annoyance, impatience, soreness, or inflammation

especially : tending to produce physical irritation

irritant

2 of 2 noun

: something that irritates

Medical Definition

irritant

1 of 2 adjective

ir·​ri·​tant ˈir-ə-tənt 

: causing irritation

specifically : tending to produce inflammation

irritant

2 of 2 noun

: something that irritates or excites

specifically : an agent by which irritation is produced

a chemical irritant