Grammar Info

N2 Lesson 10: 12/21


Must not, Cannot, Should not

Stronger than てはいけない
long form


Verb[て]+ はならない


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About てはならない

Although なくてはならない 'must do' is introduced to many learners early on, てはならない by itself carries the meaning of 'must not do', or 'cannot do'. This structure is a combination of the conjunction particle て, は, and the negated form of the う-Verb なる. Despite this ならない by itself is often considered a standalone word which may indicate that something is 'not possible', 'not permitted', or 'cannot be helped', depending on what type of word it is following.
When following verbs and ては, ならない can only mean 'cannot', or 'must not'.
  • この(いけ)では(およ)ではならない
    You must not swim in this lake.
  • (さけ)()んで運転(うんてん)てはならない
    You must not drink and drive.
  • 妊娠(にんしん)している(あいだ)はタバコを()てはならない
    You must not smoke while you are pregnant.
Caution - As a reminder, in the order from most casual to most formal, てはだめ, てはいけない, and てはならない will often be seen in sentences with no significant difference in meaning.
  • こんなことで()いていてはだめだ!
    You shouldn't cry over something like this.
  • 会議中(かいぎちゅう)携帯(けいたい)使(つか)てはいけない
    You must not use your cellphone during the meeting.
  • ここから(さき)関係者(かんけいしゃ)以外(いがい)(はい)てはならない
    You must not enter from this point forward if you are not an authorized personnel.
Due to the ならない variant being the most formal, it is also the most likely to be seen in writing or polite speech.


  • 十代(じゅうだい)(さけ)()ではならない

    Teenagers must not drink any alcohol.

    • 市民(しみん)病院(びょういん)ではタバコ()てはならない

      You must not smoke in the municipal hospital.

      • 他人(たにん)姿(すがた)()して(わら)てはならない

        You absolutely must not laugh at other people's appearances.

        • 安易(あんい)規律(きりつ)(やぶ)てはならない

          You must not simply break rules.

          • このセーター(ちぢ)むから、自分(じぶん)(あら)てはならない

            Because this sweater will shrink, you must not wash it yourself.

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