威い勢せいよく

adverb

vigorously; with energy; assertively

Describes doing something with lively energy, confidence, or forcefulness; often used for speaking, acting, or moving in a spirited manner.

• 彼かれは威い勢せいよく返へん事じをした。

  He replied vigorously.

• 選せん手しゅたちは威い勢せいよくグラウンドに飛とび出だした。

  The players energetically ran out onto the field.