great vigor; tremendous energy
Idiomatic phrase describing someone or something with overwhelming momentum, power, or influence, often used for a person at the height of their success. The literal image is of a force so strong it could knock birds out of the sky.
He is climbing the career ladder with tremendous momentum right now.
その新人歌手は飛ぶ鳥を落とす勢いで人気を集めている。
That new singer is gaining popularity with astonishing force.