てはいけない
🃏 Flashcard
てはいけない
te wa ikenai
Tap to reveal usage
must not; may not; cannot
N5
Tap to test your recall · +10 XP
📊 Pattern Stats
JLPT Level
N5
Beginner · Basic sentence structures
Reading
te wa ikenai
Post ID
50670
Patterns today
0
0 / 10 daily goal
📝 Usage Notes
must not; may not; cannot
📖 How to use it
Expresses prohibition: 'must not' or 'may not' do something.
Attaches to
Attach to the て-form of a verb, followed by はいけない. For verbs in the negative ない-form, use なくてはいけない (meaning 'must').
This pattern is the standard way to say that something is not allowed. It is formed by taking the て-form of a verb and adding はいけない. For example, 食べる becomes 食べて, so 食べてはいけない means 'must not eat'.
It is used in everyday conversation, but it is a bit strong. Teachers tell students 宿題を忘れてはいけません (You must not forget your homework). In casual speech, people often shorten it to ちゃいけない or じゃいけない, but for N5, the full form is safe.
It can also be used to say 'cannot' in the sense of a rule or social norm, not ability.
ここでタバコを吸ってはいけません。
Koko de tabako o sutte wa ikemasen.
You must not smoke here.
テストのとき、辞書を使ってはいけない。
Tesuto no toki, jisho o tsukatte wa ikenai.
You cannot use a dictionary during the test.
部屋に入るとき、靴を履いてはいけません。
Heya ni hairu toki, kutsu o haite wa ikemasen.
You must not wear shoes when entering the room.
Not てはならない
てはならない is more formal and used for rules or moral obligations, while てはいけない is common in daily conversation and can be a direct prohibition or warning.
Register
Spoken and written; neutral, but can sound strong. Common in everyday conversation, especially in the polite form てはいけません.
🎯 Quick Quiz
What does this grammar pattern mean or do?
てはいけない
📚 How to Master This Pattern
Say It Aloud
Press Hear it and repeat てはいけない three times. Feel the rhythm — grammar patterns have a natural flow.
Flip Before Reading
Always try to recall the usage before flipping the card. Struggle = learning. Every failed recall makes the next one stick harder.
Write Two Sentences
Compose two original sentences using てはいけない. One about yourself, one about something you see right now.
Spaced Review
Save this pattern and revisit at 10 min, 1 day, 3 days. Production (writing) beats recognition for grammar.
🔗 More JLPT N5 Patterns
❓ Frequently Asked Questions
What does the grammar pattern てはいけない mean?
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Must not; may not; cannot
What JLPT level is てはいけない?
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Nihoner currently groups this pattern under JLPT N5 — Beginner · Basic sentence structures. Use the level label as study guidance rather than a prediction of what will appear on an exam.
How do you use てはいけない in a sentence?
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Attach てはいけない (te wa ikenai) to the appropriate verb or noun form as described in the usage notes. Then try writing two original sentences — one about yourself and one about something around you.
Is てはいけない formal or casual Japanese?
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てはいけない is used in both casual and polite contexts. It appears frequently in everyday conversation, textbooks, and simple written materials.
How can I remember てはいけない long-term?
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Use the flashcard on this page for active recall — see the pattern, reconstruct the usage from memory, then flip. Follow with the 4-choice quiz to distinguish it from similar patterns. Review later the same day and again over the following days. Writing original sentences can help you practise using the pattern in context.