must not do (prohibition)

The te form plus wa ikemasen forbids an action: suttewa ikemasen means you must not smoke. It is firm and often seen in rules and signs. In casual speech it becomes cha dame or cha ikenai.

Examples

• ここでたばこを吸すってはいけません。

  Koko de tabako o sutte wa ikemasen.

  You must not smoke here.

• 図書館としょかんで食たべ物ものを食たべてはいけません。

  Toshokan de tabemono o tabete wa ikemasen.

  You must not eat food in the library.

Vocabulary in these examples

• ここ here
• 吸う to smoke; to inhale
• 図書館 library
• 食べ物 food
• 食べる to eat

Related patterns · Permission, obligation, ability

• 〜てもいいです may do, it is okay to do (permission)
• 〜ないでください please do not do
• 〜なければなりません must do, have to do
• 〜なくてもいいです do not have to do
• 〜ことができます can do, be able to do