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irregular

adj. · n.
US //ˌɪˈɹɛɡjəɫɝ// UK //ɪɹˈɛɡjuːlɐ// ir·reg·u·lar
  1. 1 not following a pattern (adj.)
    B2 Upper Intermediate

    not happening at regular times or following a steady pattern.

    occurring at uneven or varying intervals; lacking a predictable temporal or spatial pattern.

    Example

    The doctor noticed that the patient had an irregular heartbeat.

    Example

    The company faced significant cash flow problems due to the irregular nature of their seasonal sales and unpredictable client payments.
  2. 2 grammar (adj.)
    B1 Intermediate Technical Science

    a word that does not follow the usual rules for its endings.

    not following the standard patterns of inflection or conjugation within a specific language system.

    Example

    The verb 'to be' is the most irregular verb in the English language.

    Example

    Students often struggle with irregular past participle forms, as they must be memorised individually rather than generated through a rule-based suffix.

    Usage

    In linguistics, this usually refers to verbs, nouns, or adjectives that have unique forms.
    • nonstandard
    Pitfall
    The past tense of 'go' is a regular word.
    The past tense of 'go' is irregular.

    In grammar, 'irregular' is the specific term for words that do not follow the standard rules for endings like -ed.

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  1. 3 uneven shape (adj.)
    B2 Upper Intermediate Math

    not having a smooth or balanced shape.

    lacking symmetry, uniformity, or equal sides and angles.

    Example

    The island has a very irregular coastline with many small bays.

    Example

    The architect designed the building around an irregular plot of land, resulting in a unique floor plan with no right angles.
  2. 4 unofficial soldier (n.)
    C1 Advanced Formal

    a soldier who is not part of a country's official army.

    a member of an armed force that is not part of the official military establishment of a state.

    Example

    The forest was filled with irregulars fighting against the invading army.

    Example

    The historical account details how a small band of irregulars managed to disrupt the supply lines of the professional imperial forces for several months.
Origin

From Middle English irreguler, from Old French irreguler, from Medieval Latin or Late Latin irrēgulāris, from in- + regularis, equivalent to ir- + regular.

Word family

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