旺盛 おうせい
ōsei

Noun
na-Adjective

1. lively; vigorous; energetic; healthy; avid (e.g. desire); rich (e.g. imagination)

かれ知識 ちしき よく旺盛 おうせいである。
karewa chishikiyokuga ōsēdearu.
He is in a rage to know.
Suffix
na-Adjective

2. full of (energy, appetite, curiosity, etc.); brimming with