ならいざ知らず

If It Were, But

Level 4Sounds Like naraizashirazu

ならいざ知らず is a formal expression meaning 'It might be one thing if it were [A], but [B] is...'. It sets aside a specific case (A) as potentially understandable to emphasize how shocking, unacceptable, or impossible the actual situation (B) is.

How It Works

The expression comes from the classical Japanese 「いさ」, where 「いさ」 meant 'well, I'm not sure' and 「知らず（しらず）」 is the negative form of 'to know.' Interestingly, the modern phrase is spelled 「いざ知らず」 (with a voiced 'za') precisely because native Japanese speakers historically confused the classical 「いさ」 with the exclamation 「いざ」 meaning 'Now!' or 'Let's go!'. This pattern translates to 'I don't know about [A], but [B]...' or '[A] is one thing, but [B]...'.

Structure:

  • Noun + ならいざ知らず / はいざ知らず (Note: Do not use the plain copula 「だ」 before 「なら」. Use Noun + なら, not Noun + だなら. It can also attach to nouns marked by particles, e.g., 海外でならいざ知らず, 他人にはいざ知らず)
  • Verb (Plain Form, including た-form) + (の)ならいざ知らず / のはいざ知らず
  • い-Adjective + (の)ならいざ知らず / のはいざ知らず
  • な-Adjective (Stem) + (なの)ならいざ知らず / なのはいざ知らず

Key Nuances:
1. Contrast & Evaluation: It creates a sharp divide between a hypothetical or extreme scenario (A) and the reality (B). While often used when the second clause (B) contains a negative evaluation, criticism, dissatisfaction, disbelief, or an expression of impossibility (e.g., わけがない or 無理（むり）), it can also be used for neutral statements of fact or positive outcomes.
2. Grammar Restriction: Note that while 「なら」 can attach directly to verbs and adjectives, 「はいざ知らず」 cannot attach directly to them. They must be nominalized first using 「の」 (e.g., 行くのはいざ知らず).
3. Emphasis: Both ならいざ知らず and はいざ知らず can be used for established facts and people. However, ならいざ知らず is a stronger, more emphatic version.
4. Tone: It is frequently used for criticism (非難) or reproach, often carrying a tone of 呆れ（あきれ） (being fed up or amazed) toward the subject in Clause B, but this is not a strict requirement.
5. Formality: This is a stiff, literary expression. In casual conversation, people usually use 〜はともかく, 〜ならともかく, or ならまだしも。
6. Common Collocations: Clause A represents an extreme, hypothetical, or contrasting case where a certain outcome (good or bad) might be expected/forgiven, while Clause B represents the reality where that outcome does not apply. Common contrasting noun pairs include Time (昔（むかし） vs 今（いま）), Age (子供（こども） vs 大人（おとな）), Skill (素人（しろうと） vs プロ), and Relationship (他人（たにん） vs 家族（かぞく）).

Examples (3)

  1. 初心者ならいざ知らず、プロのあなたがこんな初歩的なミスをするなんて信じられない。

    If you were a beginner, it might be one thing, but I can't believe a professional like you would make such a basic mistake.

    Word by Word: Beginner if-it-were I-don't-know, professional 's you such basic mistake do (nominalizer) believe cannot.

    The speaker contrasts a 'beginner' (who might be excused) with a 'professional' (who should know better).

  2. 子供ならいざ知らず、いい大人が公共の場で大声で騒ぐなんてみっともない。

    It might be excusable for a child, but it is disgraceful for a full-grown adult to make such a loud noise in a public place.

    Word by Word: Child if-it-were I-don't-know, good adult public place at loud-voice with make-noise (nominalizer) disgraceful.

    The speaker uses the pattern to criticize an adult's behavior by contrasting it with a child, for whom such behavior might be tolerated.

  3. 安いアパートならいざ知らず、一流ホテルでこんなにサービスが悪いのは許せない。

    Maybe it would be expected at a cheap apartment, but such poor service at a first-class hotel is unforgivable.

    Word by Word: Cheap apartment if-it-were I-don't-know, first-class hotel at this-much service bad (nominalizer) forgive-cannot.

    The speaker sets aside the 'cheap apartment' as a place where bad service might happen to highlight how bad it is at a luxury hotel.

Common Mistakes

  • Using the copula 「だ」 before 「なら」.

    子供だならいざ知らず、大人がそんなことをしてはいけない。
    子供ならいざ知らず、大人がそんなことをしてはいけない。

    When using 「なら」 with nouns or な-adjectives, you must drop the 「だ」. Adding it is grammatically incorrect.

  • Using it in very casual, everyday situations.

    雨ならいざ知らず、買い物に行こうよ。
    雨ならともかく、買い物に行こうよ。

    While not 'wrong' grammatically, 「ならいざ知らず」 sounds overly dramatic and stiff for a simple suggestion to go shopping. 「ならともかく」 is more natural for daily life.

How It Connects

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ならいざ知らずLevel 4If It Were, But

Learn This First

To understand 'ならいざ知らず' (nara iza shirazu), learners first need to be familiar with the conditional 'nara' used for setting a topic or hypothetical condition. It is also helpful to understand similar contrastive structures that set aside one possibility to emphasize another, as this pattern specifically contrasts a potentially acceptable or understandable case with an unacceptable or surprising reality.

Words in This Pattern

いざ知らず