Definition of irregular in English:



  • 1Not even or balanced in shape or arrangement.

    ‘her features were too irregular’
    • ‘It is not that Thomas deliberately creates irregular shapes.’
    • ‘The irregular shape of the cornea distorts the image causing it to blur, unlike in a lazy eye where the eye is essentially normal.’
    • ‘This irregular arrangement of atoms not only defines a substance as glass, but also determines several of its properties.’
    • ‘Other abnormalities under high temperature stress included an irregular arrangement of the epidermal cells.’
    • ‘Each panel features an elongated, irregular rectangle painted in acrylic in red, blue or black against a contrasting hue.’
    • ‘Melanomas and other skin cancers usually have irregular shapes.’
    • ‘For larger or more irregular areas, the cables might work better.’
    • ‘After fingering about a dozen ties I choose a grey one with small irregular spots arranged in diagonal rows.’
    • ‘Unfortunately, most were not well-formed single crystals but were somewhat irregular masses.’
    • ‘Cut out the irregular shape from B and the circle from C.’
    • ‘The resultant aggregates may have many internal lipid lined compartments, which contributes to its highly irregular shape.’
    • ‘Most asteroids are very irregular in shape.’
    • ‘The spongy fabric is loose and tetrahedral, with rather irregular pores in size and shape.’
    • ‘The net result is that the cartilage is replaced from within by a somewhat irregular vascularized network of bone.’
    • ‘Dandruff is irregular in shape and does not adhere to the base of the hair.’
    • ‘Walls began to rattle, and the mirror in the entryway shook and broke into a million irregular pieces.’
    • ‘The scaphoid bone has an irregular shape, and 80% of the surface is covered by articular cartilage.’
    • ‘Electron microscopy revealed polygonal tumor cells with round nuclei having slightly irregular contours and prominent nucleoli.’
    • ‘Fractures can occur in any orientation, and they are usually curved or highly irregular in shape.’
    • ‘Most asteroids are highly irregular in shape, their miniscule gravity being too small to influence their overall outlines.’
    asymmetrical, non-uniform, uneven, crooked, misshapen, lopsided, contorted, twisted
    rough, bumpy, uneven, coarse
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    1. 1.1Occurring at uneven or varying rates or intervals.
      ‘an irregular heartbeat’
      • ‘Quivering or irregular contraction of heart muscle fibers, preventing the heart from contracting as a unit and pumping blood effectively.’
      • ‘Income can be withdrawn at irregular intervals to suit individual circumstances as long as the payments are in accordance with the above limits.’
      • ‘I've started school again, so updates will probably be in irregular intervals.’
      • ‘Postings may sometimes be irregular this week, since I'm at a conference.’
      • ‘When he finally drew away, her breathing was irregular and she appeared flustered.’
      • ‘For example, many tropical species reproduce at irregular supra-annual intervals.’
      • ‘Her head hung and she remained still for a few moments, her breathing irregular.’
      • ‘Special announcements and features appeared on a somewhat irregular basis.’
      • ‘Low blood pressure and irregular heartbeat are the most significant side effects.’
      • ‘The resultant irregular rhythm may be difficult to differentiate from atrial fibrillation.’
      • ‘The rhythm is irregular, and the rate can vary or become sinus bradycardia because of the long pauses.’
      • ‘My politicization had happened at irregular intervals during my primary and secondary school days.’
      • ‘After about 12 hours of labor, the doctor insisted on a C-section because I was bleeding heavily and the contractions were very strong and irregular.’
      • ‘She appeared to have sensed the tension building in him and her breathing was slightly irregular.’
      • ‘At the northwest corner, three to four people smoked at irregular intervals.’
      • ‘During the rest of the wintering season, surveys were conducted at irregular intervals.’
      • ‘The syndrome should be suspected in women with hirsutism, irregular menstruation, or infertility.’
      • ‘Side effects of emergency contraception are nausea, vomiting and irregular bleeding.’
      • ‘On December 4, I started experiencing mild, irregular contractions.’
      • ‘When the body's natural electrical signal becomes irregular the technology can provide synchronisation.’
      inconsistent, unsteady, uneven, shaky, fitful, patchy, variable, varying, changeable, changing, ever-changing, on-and-off, off-and-on, inconstant, erratic, haphazard, unstable, unsettled, spasmodic, sporadic, episodic, intermittent, occasional, unpunctual, wavering, fluctuating, aperiodic, unsystematic, unmethodical, capricious
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    2. 1.2Botany (of a flower) having the petals differing in size and shape; zygomorphic.
      • ‘The fasciated stem extended in one plane, and the phyllotaxy of floral primordia was irregular.’
      • ‘Irregular flowers are common in some species in the genus Commelina.’
      • ‘This is a list of species found on this site with irregular flowers.’
      • ‘The only specimen of P. ramispina bears a few small, irregular branches, but is otherwise similar to E. siniansis; it does not merit a separate taxon.’
      • ‘Irregular flowers have only a single plane of symmetry.’
  • 2Contrary to the rules or to that which is normal or established.

    ‘they were questioned about their involvement in irregular financial dealings’
    • ‘I'm not having a lot of fun these days, because my life is so irregular, so chaotic.’
    • ‘Indicated if labour is established but the contractions are of irregular intensity or duration.’
    • ‘It is no secret that some departments and individuals have overspent during the past financial year - not forgetting the irregular expenditure under investigation.’
    • ‘He is to take up the ANC's decision, which he called irregular and unacceptable, with the Local Government and Housing official.’
    • ‘The Defendant alleged in its counterclaim that it was entitled to damages for claims presented in an improper and irregular fashion.’
    • ‘The gentle formality of the house contrasts strongly with its irregular context and neighbouring suburban dwellings, but it does have precedents in New Zealand.’
    • ‘Their rather irregular position within the Church of Ireland could not really continue.’
    • ‘The couple work long hours and have very irregular, seasonal business, so they needed sound financial advice on how to use their savings wisely.’
    • ‘In the last financial year Australia had 4450 asylum-seekers arrive in irregular fashion, that is, boat people.’
    • ‘The tax situation becomes a little more complex for onshore bondholders who plan to draw down regular or irregular amounts.’
    • ‘Urge incontinence results from irregular and unexpected bladder contraction, causing the patient to feel an urgent need to relieve herself or himself.’
    • ‘If irregular bleeding started with introduction of a new contraception pill, a change in the type of pill will be considered.’
    • ‘It is claimed that leftover money from Eurostat contracts was placed in irregular reserves known as ‘financial envelopes’.’
    • ‘The union, representing about 4000 white farmers, said the judge's action was ‘highly irregular and improper’.’
    • ‘In contrast, it showed that all planetary and most irregular nebulae are traveling at very low speeds - some toward us and some away from us.’
    • ‘Memory, or at least my memory, is such an uneven and irregular thing.’
    • ‘However, this was found in contradiction of OUSU rules, necessitating an irregular by-election to be held via an extraordinary meeting of the Postgraduate Assembly.’
    • ‘Apparently such procedural irregularities, including violations of long-standing court rules, are not so irregular.’
    • ‘They're aimed at the self-employed, contract workers and those on irregular incomes and enable applicants to simply declare their incomes without having to provide any accounts or pay slips to prove it.’
    against the rules, contrary to the rules, out of order, Improper, incorrect, illegitimate, unscrupulous, unethical, unprofessional
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    1. 2.1[attributive](of troops) not belonging to regular or established army units.
      • ‘He commanded an irregular cavalry with the most striking uniforms which conquered many parts of the country for the British.’
      • ‘British troops clash with irregular forces during a raid in Basra.’
      • ‘Those operations will most certainly involve combat against both regular and irregular forces.’
      • ‘Noriega had become increasingly dictatorial, relied on irregular paramilitary units, and was involved in drug trafficking.’
      • ‘This language seems to take for granted that the armed forces of the parties to a conflict will abide by the four criteria specifically applicable to irregular troops.’
      • ‘The army and Marine Corps began to form and train units for irregular or guerrilla war operations.’
      • ‘The fighting force was to be divided into three irregular units.’
      • ‘Before the state commission army, forces were assembled from diverse sources, including mercenary bands and irregular bodies of troops raised by local nobles.’
      • ‘The Sanfedists were made into the irregular troops of the Papacy and all justice was dispensed in Church courts.’
      • ‘The Army has historically viewed irregular warfare as a temporary anomaly.’
      • ‘A better term might be irregular warfare, war against enemies unable or unwilling to field professional armies.’
      • ‘Much of the countryside remains under the control of the Afghan warlords who use heroin money to maintain their irregular armies of up to 10,000 each.’
      • ‘The biggest achievement, we think, is the formation of a system of views on the conduct of combat operations against irregular units.’
      • ‘Terrorists are illegal irregular combatants who violate international laws and murder innocent civilians; they can and should be targeted.’
      • ‘From now on, they were to be regarded as the irregular troops of a military alliance at war with the United States, and indeed the civilized world as a whole.’
      • ‘In fact, regular as well as irregular troops opposed the US in many of the conflicts Boot cites.’
      • ‘Not only did he understand the new tactics, he was also able to put them into practice using a smaller army made up of irregular troops.’
      • ‘The Army's 1899 Philippine Campaign led to important doctrine for irregular warfare.’
      • ‘The irregular rebel army is the racially and sexually integrated volunteer force of the post-Vietnam era.’
      • ‘As the theatre of war moved south, so did the smallpox, primarily affecting civilians, camp followers, and irregular troops in both armies.’
      guerrilla, underground
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    2. 2.2Grammar (of a verb or other word) having inflections that do not conform to the usual rules.
      • ‘Note that ‘to spy’ is always an irregular verb, only the third person form resembles the infinitive.’
      • ‘In some irregular verbs, these functions are served by different forms.’
      • ‘The questions required knowledge of some words, but also of an irregular verb form and some grammatical terminology.’
      • ‘However, he's mistaken when he says that ‘Esperanto is probably the only language to have no irregular verbs.’’
      • ‘The reader will not find lists of irregular verb forms or instructions for punctuating dialogue.’


  • 1A member of an irregular military force.

    • ‘Beware of irregulars and infiltrators trying to pass as civilians.’
    • ‘Personal leadership must still be exercised on these most ferocious of battlefields as we face shattered remnants and irregulars.’
    • ‘Even aside from the bloody, two and a half century-long experience of struggle against native American irregulars, when has the country waged a plausibly symmetrical conflict?’
    • ‘US forces now see the main threat as ambushes by irregulars and some foreign volunteers.’
    • ‘The mission, supposed to take roughly an hour, degenerated into a 15-hour shootout between 120 American soldiers and several thousand Somali irregulars and clan militia.’
    • ‘He's learnt that irregulars and paramilitaries can cause problems, using things like human shields.’
    • ‘Apparently, this is equally true among guerrillas and other irregulars.’
    • ‘Stricter martial law often applied to border states like Kentucky and Missouri, where populations with Confederate sympathies provided support for Confederate irregulars.’
    • ‘During the war, beginning in eastern France, it was used to refer to groups of irregulars who had organized themselves to fight the Germans.’
    • ‘After all, in both wars, most of the fighting was against irregulars, who operated among civilians.’
    • ‘The Filipino operational center of gravity was the ability to sustain its force of 100,000 irregulars in the field.’
    • ‘Other combat units went in and used better reconnaissance and fighting skills to methodically eliminate the irregulars.’
    • ‘Christian irregulars, seemingly cooperating with the military, forced the Muslim leaders to flee.’
    • ‘While repeating the Pentagon line that these irregulars were ‘forced to fight,’ Wallace acknowledged indirectly that the US military faces a hostile population.’
    • ‘The basic U.S. strength in Afghanistan is 17,000 troops of " straight-legged " infantry - conventional forces ill-prepared to handle irregulars.’
    • ‘Meanwhile, specially trained anti-guerilla units, cavalry and African scouts and irregulars did much of the actual fighting.’
    • ‘Reconstruction efforts are under way, but American troops remain targets of almost daily attacks by Iraqi irregulars.’
    • ‘In its essence, this battle was typical of all those against the Iraqi irregulars.’
    • ‘One report said that British forces faced ' lightly armed irregulars '.’
    • ‘Amitav Ghosh spent many weeks, at great personal risk, with the irregulars fighting the military regime in Burma.’
    guerrilla, underground fighter
    resistance fighter, partisan, mercenary
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  • 2North American An imperfect piece of merchandise sold at a reduced price.


Late Middle English (in the sense not conforming to rule [especially that of the Church]): via Old French from medieval Latin irregularis, from in- not + regularis (see regular).