This means 'you must not' or 'do not'. You see it in rules and signs.
Verb [dictionary form] + べからずPrimary
This means 'you must not' or 'do not'. You see it in rules and signs.
芝生に立ち入るべからず。
Do not enter the lawn.
初心忘るべからず。
One must not forget one's original intentions.
道場内では、私語を交わすべからず。
Do not engage in private conversation within the dojo.
看板には「ゴミを捨てるべからず」と書いてあった。
The sign said, 'Do not throw away trash.'
理由なくして、動物を殺傷するべからず。
One must not kill or injure animals without reason.
This grammar is like a strict rule written in stone. It comes from old Japanese words meaning 'should not be done'. This makes it sound very strong and official.
This is different from 〜べからざる. That form means 'not allowed' and comes before a noun. This is also different from 〜まじき. 〜べからず means 'you must not do this'. 〜まじき means 'you should not do this' because it is not proper for you.
Don't use this when you talk to friends. For example, you would not say, "そこへ行くべからず" to a friend.
Use this when you want to say "do not" in a very strong way. It is like a rule from a boss or a sign. It makes the rule sound old and important. It is not your own idea. It is a rule for everyone.
Contrasts with(4)
More formal alternatives(1)
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