ball of fire

Noun

idiomatic

(idiomatic) A person who is especially hard-working, high-achieving, ambitious, or active.

Japanese Meaning

非常に活発で、エネルギッシュな、努力家で成果を追求する人 / 意欲的で積極的、活力あふれる人物

Even with a hectic schedule, Maria is a ball of fire who finishes every project ahead of time.

どんなに多忙でも、マリアはいつも期日より早くプロジェクトを終わらせる行動力あふれる人だ。

Sense（1）

(idiomatic) A person who is especially hard-working, high-achieving, ambitious, or active.

"I wonder how fast this feller is? Ever heard?"

"They seem to think he's a whirlin' ball of fire, but that don't worry you none, does it?"

balls of fire

（ plural ）