欢快 (huān kuài): cheerful and lighthearted; lively

The children ran happily back and forth on the grass, and their laughter carried far.

Hearing the good news, a cheerful smile appeared on her face.

At the wedding, the band played cheerful music, and the guests all started dancing.

In the park on the weekend, the elderly people sang joyfully, enjoying the warm sunshine.

When the puppy saw its owner come home, it wagged its tail happily and circled around him.