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

Research finds that because women have smaller bronchial tubes and lungs than men, inhaling irritants like tobacco smoke and pollutants can be more damaging. —Helen Carefoot, Flow Space, 20 Nov. 2025

Wight also said a chemical irritant was deployed. —Wcco Staff, CBS News, 18 Nov. 2025

Adjective

The agents deployed a chemical irritant on the crowd and physically removed some protesters who were blocking four federal vehicles from leaving. —Frankie McLister, CBS News, 19 Nov. 2025

Who was this irritant who had eluded the most sophisticated lawmen in the country, thanks to the triviality of his crimes? —David Grann, New Yorker, 19 Oct. 2025

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