irregular

C1 (High frequency within its conceptual domain)
UK/ɪˈreɡjələ(r)/US/ɪˈreɡjələr/

Formal to neutral. Common in academic, technical, and everyday discourse.

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Definition

Meaning

Not following the normal or expected pattern, rule, or arrangement.

Characterised by inconsistency, unevenness, or deviation from a standard. Can refer to shapes, timing, behaviour, or grammatical forms.

Linguistics

Semantic Notes

The core sense is the negation of 'regular'. It is polysemous, applying to physical shape (an irregular coastline), timing/occurrence (irregular attendance), behaviour/legality (irregular practices), and grammar (irregular verbs). Context heavily determines the specific nuance.

Dialectal Variation

British vs American Usage

Differences

Minimal. Slight preference in UK English for 'irregular' in medical contexts (e.g., 'irregular heartbeat'). In military/paramilitary contexts, 'irregulars' (noun) for non-standard forces is common in both.

Connotations

Equally neutral/descriptive in both varieties. Can carry negative connotations of unreliability or non-conformity depending on context.

Frequency

Comparably frequent in both corpora.

Vocabulary

Collocations

strong
irregular verbirregular heartbeathighly irregularirregular shapeirregular pattern
medium
irregular attendanceirregular intervalsirregular surfaceirregular paymentsirregular behaviour
weak
somewhat irregularbecome irregularseem irregulardeclare irregularincreasingly irregular

Grammar

Valency Patterns

[be] irregular[be] irregular in [NP/V-ing] (e.g., irregular in shape)[NP] show irregular [NP] (e.g., shows irregular growth)highly/quite/somewhat irregular

Vocabulary

Synonyms

Strong

anomalousaberrantnonstandardasymmetrical

Neutral

uneveninconsistenterraticvariableunpredictable

Weak

occasionalsporadicpatchyunsteady

Vocabulary

Antonyms

regularconsistentsteadypredictableuniformsymmetrical

Phrases

Idioms & Phrases

  • Against all rules and regulations (implies an 'irregular' procedure)
  • To march to the beat of a different drum (suggests irregular behaviour in a positive light)

Usage

Context Usage

Business

Referring to non-standard financial reports, uneven sales figures, or non-compliance with procedures.

Academic

Describing anomalous data, exceptions to rules (e.g., in linguistics or biology), or non-periodic phenomena.

Everyday

Discussing sleep patterns, train schedules, or the shape of an object.

Technical

In medicine (irregular pulse), grammar (irregular plural), mathematics (irregular polygon), or geology (irregular strata).

Examples

By Part of Speech

verb

British English

  • The council voted to irregularise the previously accepted procedure.

adverb

British English

  • The buses run quite irregularly on bank holidays.

American English

  • He attended meetings irregularly, which concerned his manager.

adjective

British English

  • The patient presented with an irregular pulse.

American English

  • The coastline is rugged and irregular.

Examples

By CEFR Level

A2
  • My desk has an irregular shape.
  • Some verbs in English are irregular, like 'go' and 'see'.
B1
  • Her work hours are quite irregular, so it's hard to plan meetings.
  • The garden path was made from irregular flat stones.
B2
  • An audit revealed several irregular financial transactions that required explanation.
  • The data showed an irregular pattern that didn't fit any of our existing models.
C1
  • The tribunal deemed the election process highly irregular and ordered a revote.
  • Geopolitically, the region has been a hotbed for irregular warfare for decades.

Learning

Memory Aids

Mnemonic

Think: 'IR-REGULAR' = 'NOT REGULAR'. A regular soldier stands in a straight line; an IRregular soldier stands in a crooked, uneven line.

Conceptual Metaphor

REGULARITY IS ORDER / IRREGULARITY IS DISORDER. Also, REGULARITY IS A SMOOTH PATH / IRREGULARITY IS A BUMPY PATH.

Watch out

Common Pitfalls

Translation Traps (for Russian speakers)

  • Avoid directly using 'нерегулярный' for all contexts. For 'irregular verb', use 'неправильный глагол'. For 'irregular shape', 'неровная форма' or 'неправильная форма' is better. 'Irregular attendance' is 'нерегулярное посещение', but 'irregular practices' are 'незаконные/недобросовестные практики'.

Common Mistakes

  • Confusing 'irregular' with 'rare' (e.g., 'He comes irregularly' vs. 'He comes rarely' – the former means unpredictably, the latter infrequently). Overusing 'irregular' as a synonym for 'bad'. Incorrect stress: /ˈɪrɛɡjələ/ instead of /ɪˈrɛɡjələ/.

Practice

Quiz

Fill in the gap
The investigator found the paperwork to be highly , with dates missing and signatures inconsistent.
Multiple Choice

In which context does 'irregular' most strongly imply something illegal or against official rules?

FAQ

Frequently Asked Questions

No, it is descriptive. An 'irregular shape' can be interesting or artistic. 'Irregular verbs' are simply a grammatical category. Negativity depends on context (e.g., 'irregular heartbeat' is negative, 'irregular pattern' is neutral).

'Irregular' is the broadest, meaning 'not regular'. 'Uneven' often refers specifically to physical surface or distribution. 'Erratic' implies unpredictable and capricious change, often in behaviour or movement.

There are around 200-250 common irregular verbs in English, though the exact number depends on how one counts derivations and archaic forms.

Yes, though less common. It can refer to a soldier not part of the regular army ('the militia and irregulars'), or an item (especially in retail) that is slightly flawed or non-standard ('sold as an irregular').

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