Prohibition: ใใฆใฏใใใชใ / ใใฆใฏใใใพใใ
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
Example Sentences
Teacher's Advice
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
- โขChoosing between ~te mo ii (allowed) and ~te wa ikemasen (forbidden) (N5)
- โขReading signs and rules using this grammar (N5)
- โขUnderstanding ~te wa naranai in written/formal texts (N4)
How Strong Does This Sound?
~ใฆใฏใใใพใใ is not the only way to prohibit something in Japanese, and it is not the softest one. In daily conversation between friends, ใใกใใ ใ (casual, from ใใฆใฏใ ใ) is far more common and sounds like a gentle 'you shouldn't' rather than an official rule. Parents say it to children constantly.
~ใฆใฏใใใพใใ sits in the middle: firm enough for a teacher addressing a class or a sign in public, but not the level you would see in a legal document or an official regulation, where ใใฆใฏใชใใชใ takes over. Choosing the wrong register is not grammatically wrong, but ~ใฆใฏใใใพใใ from a child to an adult, or ใใกใใ ใ on an official notice, both sound out of place to a native speaker.
Related Grammar
Know the Rules
Practice making sentences about what you must not do using real-life scenarios.