起劲 (qǐ jìn): energetic; vigorous; enthusiastic

The children were playing soccer on the playground with great energy; they didn't even hear the dismissal bell ring.

Old Zhang wiped his sweat while energetically telling his neighbors about his fishing experience yesterday; everyone listened with great interest.

In order to prepare for the school singing competition, she practiced energetically every day after school, and her voice even became a bit hoarse.

Everyone was energetically discussing going hiking on the weekend when suddenly the power went out, and the room was pitch black.