JLPT Grammar N5: ~ちゃいけない / ~じゃいけない – Must Not Do
Meaning & Usage ~ちゃいけない and ~じゃいけない are casual spoken forms of ~てはいけない, which expresses a prohibition: “must not do.” Translation: “You must not…” Form: Verb-て-form + ちゃいけない (for verbs ending in …+て) Verb-て-form + じゃいけない (after い-adj/な-adj/verbs ending in …+で) Example Sentences ここでタバコを吸っちゃいけない。 You must not smoke here. 宿題を忘れちゃいけないよ。 You must not forget your homework. […]