A four-character idiom meaning 'great talents mature late' — someone who achieves greatness later in life.
彼は若いころは目立たなかったが、大器晩成の人だ。
He didn't stand out when young, but he is someone who matures late and achieves greatness.
大器晩成という言葉は、若手を励ますときにも使われる。
The phrase '大器晩成' is also used to encourage young people.
この作家の評価は遅れてきたが、まさに大器晩成だ。
The writer's recognition came late, but it's exactly a case of 'great talents mature late.'