翩翩 is a reduplicated adjective/adverb that describes light, graceful, and elegant movement — often used for dancing, fluttering (like butterflies or leaves), or someone's poised demeanor. It carries a literary or poetic register; you'll encounter it in descriptive prose, classical poetry, and formal writing rather than casual conversation. As an adverb, it modifies verbs like 起舞 (to dance) or 飞 (to fly).