Japanese Grammar

Prohibition: ใ€œใฆใฏใ„ใ‘ใชใ„ / ใ€œใฆใฏใ„ใ‘ใพใ›ใ‚“

To say 'You must not' or 'It is forbidden to', Japanese uses the ~te wa ikenai form. This is how rules, warnings, and prohibitions are expressed.

How to say 'You must not'

While ~te mo ii means 'It's okay to do X', the opposite is ~te wa ikenai / ~te wa ikemasen, which means 'It's NOT okay / You must NOT do X'.

This is the standard form used for rules (No photography!), parental warnings (Don't do that!), and official prohibitions.

The casual form is ~te wa dame (da/desu), which is softer and used in everyday speech. The more formal/literary form is ~te wa naranai.

Conjugation Rules

Making the Prohibition Form
Te-form
โ†’Te-form + ใฏใ„ใ‘ใพใ›ใ‚“ (wa ikemasen)
It is not allowed to...
้ฃŸในใ‚‹ -> ้ฃŸในใฆ
โ†’้ฃŸในใฆใฏใ„ใ‘ใพใ›ใ‚“ใ€‚
You must not eat.
ๅ…ฅใ‚‹ -> ๅ…ฅใฃใฆ
โ†’ๅ…ฅใฃใฆใฏใ„ใ‘ใพใ›ใ‚“ใ€‚
You must not enter.
Casual vs Polite vs Formal
Casual
โ†’ใ€œใฆใฏใ ใ‚ (te wa dame)
No! / Don't! (said by parents to children)
Polite
โ†’ใ€œใฆใฏใ„ใ‘ใพใ›ใ‚“ (te wa ikemasen)
You must not... (standard)
Formal / Written
โ†’ใ€œใฆใฏใชใ‚‰ใชใ„ (te wa naranai)
One must not... (legal, very formal)

Example Sentences

ใ“ใ“ใงใ‚ฟใƒใ‚ณใ‚’ๅธใฃใฆใฏใ„ใ‘ใพใ›ใ‚“ใ€‚
Koko de tabako o sutte wa ikemasen.
You must not smoke here.
ๅ˜˜ใ‚’ใคใ„ใฆใฏใ ใ‚ใ ใ‚ˆใ€‚
Uso o tsuite wa dame da yo.
You must not tell lies. (Casual, parental tone)
ๆณ•ๅพ‹ใ‚’็ ดใฃใฆใฏใชใ‚‰ใชใ„ใ€‚
Houritsu o yabutta wa naranai.
One must not break the law. (Formal/Written)

Teacher's Advice

Permission vs Prohibition

A very common exam trap is mixing up ~te mo ii (OK to do) and ~te wa ikemasen (must NOT do). Remember the key: 'mo ii' has the positive word 'ii' (good/okay). 'wa ikemasen' literally means 'does not go well' โ†’ NOT okay.

JLPT Exam Patterns

  • โ€ขChoosing between ~te mo ii (allowed) and ~te wa ikemasen (forbidden) (N5)
  • โ€ขReading signs and rules using this grammar (N5)
  • โ€ขUnderstanding ~te wa naranai in written/formal texts (N4)

Know the Rules

Practice making sentences about what you must not do using real-life scenarios.

Start Practice โ†’
Japanese ใ€œใฆใฏใ„ใ‘ใชใ„ (~te wa ikenai): Must Not | Nihongo Pass