べからざる

べからざる is a very formal, old-fashioned expression that states absolute prohibition.

Core idea:

• “X must never be done”

• “X is unacceptable”

• “X is something that should not exist”

Important nuance:

• Stronger than ～てはいけない

• Sounds authoritative and categorical

• Often implies moral judgment or principle

• No room for exceptions

This grammar is commonly found in:

• laws and regulations

• ethical rules and principles

• academic or philosophical writing

• official statements

• JLPT N1 reading passages

It is almost never used in spoken Japanese.