n.the freshness and vitality characteristic of a young person

同義詞：youthjuvenility

1. Her youthfulness is evident in her bright smile and energetic personality.
   她的年輕氣質(zhì)在她燦爛的微笑和充滿活力的個性中展現(xiàn)無遺。
2. Despite his age, he still maintains a remarkable youthfulness.
   盡管年紀已大，他依然保持著驚人的青春氣息。