Translation

はつらつとした迅速さ / 進んで素早くすること / 快活な意欲

Meaning

Alacrity is cheerful readiness and quick willingness to do something. It combines speed with eagerness, so it is not just doing a task fast under pressure.

Examples

• 彼女はその難しい依頼を喜んですぐに引き受けた。
  She accepted the difficult request with alacrity.
• 学生たちは驚くほどの意欲と速さで実験を始めた。
  The students began the experiment with surprising alacrity.