Nearby words

  1. irrefragable,
  2. irrefrangible,
  3. irrefutable,
  4. irreg.,
  5. irregardless,
  6. irregular astigmatism,
  7. irregular bone,
  8. irregular dentin,
  9. irregular flower,
  10. irregular galaxy

Origin of irregular

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

SYNONYMS FOR irregular
1. unsymmetrical, uneven. 2. unmethodical, unsystematic; disorderly, capricious, erratic, eccentric, lawless. 4. anomalous, unusual. 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).

Related formsir·reg·u·lar·ly, adverbqua·si-ir·reg·u·lar, adjectivequa·si-ir·reg·u·lar·ly, adverb Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for irregular

British Dictionary definitions for irregular



lacking uniformity or symmetry; uneven in shape, position, arrangement, etc
not occurring at expected or equal intervalsan irregular pulse
differing from the normal or accepted practice or routine
not according to established standards of behaviour; unconventional
(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
of or relating to guerrillas or volunteers not belonging to regular forcesirregular troops
(of flowers) having any of their parts, esp petals, differing in size, shape, etc; asymmetric
US (of merchandise) not up to the manufacturer's standards or specifications; flawed; imperfect


a soldier not in a regular army
(often plural) US imperfect or flawed merchandiseCompare second 1 (def. 15)
Derived Formsirregularly, 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

Word Origin and History for irregular
Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for irregular




Not straight, uniform, or symmetrical, as facial features.
Of uneven rate, occurrence, or duration, as a heartbeat.
Deviating from a type; atypical.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.