Quiz: Remember the definition of mal de mer?


[ih-reg-yuh-ler] /ɪˈrɛg yə lər/
without symmetry, even shape, formal arrangement, etc.:
an irregular pattern.
not characterized by any fixed principle, method, continuity, or rate:
irregular intervals.
not conforming to established rules, customs, etiquette, morality, etc.:
highly irregular behavior.
not according to rule, or to the accepted principle, method, course, order, etc.
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.
Military. (formerly, of troops) not belonging to an organized group of the established forces.
flawed, damaged, or failing to meet a specific standard of manufacture:
a sale of irregular shirts.
  1. not uniform.
  2. (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.
deviating or experiencing deviations from a normally regular or cyclic body function, as bowel habits or menstruation.
(of a stock or commodity market) of mixed market activity; showing no clear up or down trend.
a person or thing that is irregular.
Commerce. a product or material that does not meet specifications or standards of the manufacturer, as one having imperfections in its pattern.
Military. a soldier or combatant not of a regular military force, as a guerrilla or partisan.
1350-1400; < Late Latin irrēgulāris (see ir-2, regular); replacing Middle English irreguler < Middle French
Related forms
irregularly, adverb
quasi-irregular, adjective
quasi-irregularly, adverb
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). Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
Cite This Source
Examples from the web for irregular
  • The new command calls up a random generator that makes the character outlines irregular.
  • The resulting scar tissue blocks the abnormal flow of electrical signals that can cause irregular heartbeats.
  • Data in regular time series is spaced at regular intervals, while irregular time series data is intermittent.
  • irregular periods from any cause may make it more difficult to conceive.
  • His office hours were irregular and sometimes held on a mountaintop.
  • The hiring of irregular staff, and the use of outside agencies working under contract, has been bad for standards and morale.
  • Galaxies that are not spiral or elliptical are called irregular galaxies.
  • Symptoms can also include tremors and irregular breathing.
  • Ectopic heartbeats are small variations in an otherwise normal heartbeat that causes an irregular pulse.
  • Others are irregular fragments of such planetoids brought about by collisions.
British Dictionary definitions for irregular


lacking uniformity or symmetry; uneven in shape, position, arrangement, etc
not occurring at expected or equal intervals: an 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 forces: irregular 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 pl) (US) imperfect or flawed merchandise Compare second1 (sense 15)
Derived Forms
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
Cite This Source
Word Origin and History for irregular

late 14c., "not in conformity with Church rules," from Old French irreguler (13c., Modern French irrégulier), from Medieval Latin irregularis, from assimilated form of in- "not, opposite of" (see in- (1)) + Latin regularis (see regular (adj.)). General sense is from late 15c.


"a soldier not of the regular army," 1747, from irregular (adj.).

Online Etymology Dictionary, © 2010 Douglas Harper
Cite This Source
irregular in Medicine

irregular ir·reg·u·lar (ĭ-rěg'yə-lər)

  1. Not straight, uniform, or symmetrical, as facial features.

  2. Of uneven rate, occurrence, or duration, as a heartbeat.

  3. 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.
Cite This Source

Word of the Day

Difficulty index for irregular

Most English speakers likely know this word

Word Value for irregular

Scrabble Words With Friends

Quotes with irregular