まかりならぬ

expression

not be allowed; must not

Archaic or highly formal expression meaning something is absolutely not permitted. Often used in historical or dramatic contexts. In modern Japanese, ～てはならない or ～てはいけない are more common.

• この門もんをくぐることはまかりならぬ。

  Passing through this gate is not allowed.

• そのような振ふる舞まいはまかりならぬと、殿とのは厳きびしく言いい渡わたした。

  The lord sternly declared that such behavior must not be tolerated.