JLPT N5 grammar · The TE-Form Core
~てはいけません: meaning, usage and examples
~てはいけません means: must not... (strong prohibition).
How to form it
＜Verb-ては＞ + いけません / いけない
Examples
タバコを吸ってはいけません。ここは禁煙です。
You must not smoke. This is a no-smoking area.
ここで写真をとってはいけません。
You must not take pictures here.
図書館で話してはいけません。
You must not talk in the library.
この水を飲んではいけません。
You must not drink this water.
When to use it
Strong prohibition: 'you must not do X'. Often seen on signs or rules.
Nuance
いけない is the plain/casual form. いけません is polite. ならない is even more formal/written.
Compare
〜てもいいですか asks for permission. 〜てはいけません denies permission emphatically.
Tip: 〜はいけない can be shortened in speech to 〜ちゃいけない (via てはいけない → ちゃいけない).
More on this in The Japanese te-form.
More in The TE-Form Core
- Verb Group [dictionary-form] Version: Verb groups by dictionary form: Group 1 (-u verbs, including some -iru/-eru verbs such as 帰る and 走る), Group 2 (-iru/-eru verbs such as 食べる and 見る), Group 3 (irregular: する and 来る)
- Verb Group [masu-form] Version: Masu form: Group 1 verbs change the final -u to -i + ます (飲む → 飲みます); Group 2 verbs drop る + ます (食べる → 食べます, 見る → 見ます); する → します, 来る → 来ます
- Plain style [Verb]: (Conjugation for verbs, plain form)
- Polite style [Verb]: (Conjugation for verbs, polite form)
- Verb て形 (Te form): Verb te-form (used for requests, joining actions, etc.)
- ~て: (used to join two or more sentences/actions together)
- ~てください / 〜ないでください: please do... / please don't do...
- ~ています: (1. an action in progress) (2. a resulting condition/state)
- ~てもいいですか: may I [Verb]? (asking for permission)
Frequently asked questions
What does ~てはいけません mean?
Must not... (strong prohibition). Example: タバコを吸ってはいけません。ここは禁煙です。 (You must not smoke. This is a no-smoking area.)
How do you form ~てはいけません?
＜Verb-ては＞ + いけません / いけない. 〜はいけない can be shortened in speech to 〜ちゃいけない (via てはいけない → ちゃいけない).