不規則|ふきそくfukisoku[2]nakadaka (mid-high)

1. na-adjective, nounirregular; unsystematic; unsteady; disorderly
   生理せいりが不規則ふきそくです。↗

   My menstrual cycle is irregular.

• Synonym変則へんそくWrittenWritten/formal word for arrangements that deviate from the standard rules, as in 「変則的な日程」; 「不規則」 is about lacking a pattern.
• SynonymイレギュラーNeutralLoanword for something unconventional or unexpected, and for a ball's bad bounce in tennis or baseball; 「不規則」 is about lacking a regular pattern.
• Related型破りかたやぶりNeutralDescribes breaking with convention, often approvingly, as in 「型破りな発想」; 「不規則」 is about lacking a regular pattern.
• Related異例いれいNeutralRefers to something unprecedented or against usual practice, as in 「異例の昇進」; 「不規則」 is about changes with no set pattern.
• Related凸凹でこぼこNeutralDescribes bumpy, uneven surfaces, and by extension patchy, uneven levels; 「不規則」 is about irregular timing or arrangement.
• RelatedちぐはぐNeutralMeans mismatched or not fitting together, as in 「ちぐはぐな服装」; 「不規則」 is about lacking a regular pattern.
• Related異常いじょうNeutralMeans abnormal or anomalous and usually carries a negative sense; 「不規則」 merely states that there is no regular pattern.
• Related一風変わったいっぷうかわったNeutralMeans quirky or one-of-a-kind, usually with a positive flavor; 「不規則」 is simply about having no regular pattern.
• Relatedバラ付きばらつきNeutralNoun for unevenness or variation in data or quality; 「不規則」 is about irregular timing or arrangement.
• Related非定型ひていけいWrittenWritten/formal term for lacking a fixed form or being atypical, as in 「非定型詩」; 「不規則」 is about lacking regularity.
• Antonym定期的ていきてきNeutralAlso opposite to 「不規則」 in regularity: describes things done at fixed intervals, like periodic or routine tasks.
• Antonym規則正しいきそくただしいNeutralThe direct opposite in terms of regularity: describes routines and schedules that are orderly and follow a set pattern.

Use 「不規則」 for routines, schedules or arrangements that follow no regular pattern. For uneven quality or data use 「ばらつき」, for bumpy or patchy surfaces 「凸凹」; for departures from convention use 「異例」 or 「変則」; for bold, unconventional flair use 「型破り」. The opposites are 「規則正しい」 and 「定期的」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 規則きそく正ただしくないこと。また、その様子ようす。