1Extremely important or serious, such that it cannot be treated lightly; used for grave accidents, problems, or responsibilities.
これは会社の将来を左右する重大な決断だ。
This is a critical decision that will determine the company's future.
彼は重大な責任を負っている。
He bears a heavy responsibility.
その事件は社会に重大な影響を及ぼした。
That incident had a serious impact on society.
手術中に重大なミスがあったことが分かった。
It turned out that a serious mistake was made during the surgery.