[ ih-reg-yuh-ler ]
See synonyms for: irregularirregularsirregularly on

  1. without symmetry, even shape, formal arrangement, etc.: an irregular pattern.

  2. not characterized by any fixed principle, method, continuity, or rate: irregular intervals.

  1. not conforming to established rules, customs, etiquette, morality, etc.: highly irregular behavior.

  2. not according to rule, or to the accepted principle, method, course, order, etc.

  3. Grammar. not conforming to the prevalent pattern or patterns of formation, inflection, construction, etc., of a language; having a rule descriptive of a very small number of items: The English verbs “keep” and “see” are irregular in their inflections.

  4. Military. (formerly, of troops) not belonging to an organized group of the established forces.

  5. flawed, damaged, or failing to meet a specific standard of manufacture: a sale of irregular shirts.

  6. Botany.

    • not uniform.

    • (of a flower) having the members of some or all of its floral circles or whorls differing from one another in size or shape, or extent of union.

  7. deviating or experiencing deviations from a normally regular or cyclic body function, as bowel habits or menstruation.

  8. (of a stock or commodity market) of mixed market activity; showing no clear up or down trend.

  1. a person or thing that is irregular.

  2. Commerce. a product or material that does not meet specifications or standards of the manufacturer, as one having imperfections in its pattern.

  1. Military. a soldier or combatant not of a regular military force, as a guerrilla or partisan.

Origin of irregular

First recorded in 1350–1400; from Late Latin irrēgulāris (see ir-2, regular); replacing Middle English irreguler, from Middle French

synonym study For irregular

4. Irregular, abnormal, exceptional imply a deviation from the regular, the normal, the ordinary, or the usual. Irregular, not according to rule, refers to any deviation, as in form, arrangement, action, and the like; it may imply such deviation as a mere fact, or as regrettable, or even censurable. Abnormal means a deviation from the common rule, often implying that this results in an aberrant or regrettably strange form or nature of a thing: abnormal lack of emotion; A two-headed calf is abnormal. Exceptional means out of the ordinary or unusual; it may refer merely to the rarity of occurrence, or to the superiority of quality: an exceptional case; an exceptional mind. Because of the stigma of abnormal, exceptional is today frequently substituted for it in contexts where such a euphemism may be thought to be appropriate: a school for exceptional children (children who are abnormal in behavior, mental capacity, or the like).

Other words for irregular

Other words from irregular

  • ir·reg·u·lar·ly, adverb
  • qua·si-ir·reg·u·lar, adjective
  • qua·si-ir·reg·u·lar·ly, adverb

Words Nearby irregular Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use irregular in a sentence

British Dictionary definitions for irregular


/ (ɪˈrɛɡjʊlə) /

  1. lacking uniformity or symmetry; uneven in shape, position, arrangement, etc

  2. not occurring at expected or equal intervals: an irregular pulse

  1. differing from the normal or accepted practice or routine

  2. not according to established standards of behaviour; unconventional

  3. (of the formation, inflections, or derivations of a word) not following the usual pattern of formation in a language, as English plurals ending other than in -s or -es

  4. of or relating to guerrillas or volunteers not belonging to regular forces: irregular troops

  5. (of flowers) having any of their parts, esp petals, differing in size, shape, etc; asymmetric

  6. US (of merchandise) not up to the manufacturer's standards or specifications; flawed; imperfect

  1. a soldier not in a regular army

  2. (often plural) US imperfect or flawed merchandise: Compare second 1 (def. 15)

Derived forms of irregular

  • irregularly, adverb

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