See more synonyms for irritant on
  1. anything that irritates.
  2. Physiology, Pathology. a biological, chemical, or physical agent that stimulates a characteristic function or elicits a response, especially an inflammatory response.

Origin of irritant

1630–40; < Latin irrītant- (stem of irrītāns), present participle of irrītāre to irritate; see -ant
Related formsir·ri·tan·cy, nounnon·ir·ri·tan·cy, nounnon·ir·ri·tant, adjectiveun·ir·ri·tant, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words for irritant

bother, trouble, nuisance, burden, aggravation

Examples from the Web for irritant

Contemporary Examples of irritant

Historical Examples of irritant

British Dictionary definitions for irritant


  1. causing irritation; irritating
  1. something irritant
Derived Formsirritancy, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for irritant

1630s, from Latin irritantem (nominative irritans), present participle of irritare (see irritate). As a noun, from 1802.

Online Etymology Dictionary, © 2010 Douglas Harper

irritant in Medicine


  1. Causing irritation, especially physical irritation.
  1. A source of irritation.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.