expression, ichidan verb
have a moment of glory; enjoy brief success; flourish for a while
Often used when someone achieves a notable but temporary success, especially before retiring, leaving a position, or ending a career. The image is of a single flower blooming briefly.
定年退職前に一花咲かせたいと思って、新しいプロジェクトに挑戦した。
Wanting to have one last moment of glory before retirement, I took on a new project.
彼は若い頃に一花咲かせたが、その後はぱっとしなかった。
He enjoyed a brief stint of success when he was young, but after that he didn't do much.