Translation guide
The English word 'irregular' covers a wide range of meanings including not following rules, uneven patterns, non-standard forms, and occasional occurrences. This guide organizes the most useful Japanese expressions by these core meanings.
Describing something that deviates from standard rules, procedures, or expectations.
The most direct and common translation for 'irregular' in the sense of not following a regular pattern or rule. Used for schedules, shapes, verbs, etc.
彼は不規則な生活を送っている。
He leads an irregular lifestyle.
この動詞は不規則変化をする。
This verb has an irregular conjugation.
Emphasizes deviation from normal rules or methods, often used for procedures or systems.
変則的な手続きで承認された。
It was approved through an irregular procedure.
A loanword from English, commonly used in business or casual contexts to mean something out of the ordinary or an exception.
今日はイレギュラーな対応が必要だ。
We need to handle this irregularly today.
Describing shapes, surfaces, or patterns that are not uniform or smooth.
Used for things that are uneven in size, shape, or alignment, like teeth, vegetables, or rows.
不揃いの野菜の方が新鮮に見える。
Irregularly shaped vegetables look fresher.
Describes a bumpy, uneven surface. Often used for roads or skin.
Can also be used for irregular patterns or shapes, but less specific than 不揃い.
Describing events that happen from time to time, not regularly scheduled.
Means 'irregular' in the sense of not having a fixed time or schedule. Common for meetings, publications, or work.
この会議は不定期に開かれる。
This meeting is held irregularly.
彼は不定期にアルバイトをしている。
He works part-time on an irregular basis.
Simply means 'sometimes' or 'occasionally'. Less formal and very common in speech.
Describing something that is not typical or deviates from the norm, often in a technical or medical context.
Means 'abnormal' or 'irregular' in a medical, technical, or statistical sense. Can imply something is wrong.
心電図に不規則な波形が見られる。
An irregular waveform is seen on the ECG.
異常気象が続いている。
Irregular weather patterns continue.
Used for something that deviates from the norm, especially in rules or systems. Similar to 変則的 but as a noun.
Referring to words that do not follow standard conjugation or declension patterns.
The standard term for 'irregular verb'.
英語には不規則動詞がたくさんある。
English has many irregular verbs.
Refers to irregular conjugation or declension in general.
この名詞は不規則変化をする。
This noun has an irregular declension.
不規則 (fukisoku) means lacking a regular pattern or rule, while 不定期 (futeiki) specifically means not having a fixed time or schedule. Use 不規則 for shapes, verb forms, or lifestyle; use 不定期 for events or publications.
イレギュラー is a loanword and sounds casual. In formal writing or technical contexts, prefer 不規則 or 変則的.
この道はでこぼこしていて歩きにくい。
This road is irregular and hard to walk on.
不規則な形の石
an irregularly shaped stone
彼は時々遅刻する。
He is occasionally late.
変則的な勤務体系
an irregular work system