重じゅう大だい事じ

noun

very serious matter; momentous event

Used for matters of grave concern or events with significant consequences. Often appears in formal or news contexts.

• この問もん題だいは国こっ家かの重じゅう大だい事じだ。

  This issue is a matter of grave national concern.

• 彼かれの辞じ任にんは会かい社しゃにとって重じゅう大だい事じだった。

  His resignation was a momentous event for the company.