Translation guide
A guide to expressing 'should not' in Japanese, covering negative obligation, prohibition, and advisability.
Expressing that something is not allowed, not right, or must not be done.
A common pattern meaning 'must not do' or 'should not do'. Used in rules, warnings, and personal advice. The verb is in て-form.
ここでタバコを吸ってはいけません。
You must not smoke here.
そんなことを言ってはいけないよ。
You shouldn't say things like that.
A more casual and direct way to say 'must not do'. Often used in spoken Japanese.
Expressing that something is unlikely or not expected to happen.
Indicates strong conviction that something cannot or should not be the case. Attaches to the plain form.
彼がそんなことをするはずがない。
He would never do such a thing. (He should not do such a thing.)
Similar to はずがない, but slightly more logical or emphatic. 'There's no reason that...'
てはいけない is a general prohibition or rule, while べきではない expresses a moral or logical 'should not'. てはいけない is more common in everyday speech.
ここで走ってはいけない。
You must not run here. (rule)
約束を破るべきではない。
One should not break promises. (moral)
There is no single Japanese word for 'should not'. Avoid translating directly as すべきではない in all cases; it can sound overly formal or moralistic. Use てはいけない for everyday prohibitions.
You shouldn't be late.
A more formal pattern meaning 'should not do', based on moral or logical grounds. Attaches to the dictionary form of the verb.
人は嘘をつくべきではない。
People should not lie.
Literally 'it's better not to do', this is a softer way to advise against something. Attaches to the negative plain form.
今日は出かけないほうがいいよ。
You shouldn't go out today.
A blunt, informal prohibition used in strong commands or warnings. Attaches to the dictionary form. Mostly used by men or in rough speech.
触るな！
Don't touch!
It can't be that easy. (It shouldn't be that easy.)