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

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

The June 14 protests were mostly peaceful until protesters and local law enforcement officers clashed in downtown LA, leading to officers deploying chemical irritants and flash bang grenades at civilians. —Madeline Armstrong, Oc Register, 18 Oct. 2025

Have protective goggles or shatter-resistant glasses (for tear gas or irritants). —Jalen Williams, Freep.com, 17 Oct. 2025

Adjective

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

The Two-Stage Tear Cascade While past research had already identified the irritant in onions—known to chemists as propanethial S-oxide—this study is the first to explain how the sulfur compound reaches a cook's eyes. —Maria Morava, MSNBC Newsweek, 8 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