na-adjective, noun
vigorous; energetic; lively; healthy
Describes strong, flourishing states of abstract qualities like energy, appetite, curiosity, or imagination. Often used in formal or written contexts.
彼は旺盛な好奇心で新しい分野に挑戦した。
With vigorous curiosity, he took on a new field.
Even in old age, his appetite is healthy and strong.
noun, used as a suffix, na-adjective
full of; brimming with
Suffix-like use attaching to nouns that express a drive or quality (e.g., 好奇心旺盛, 食欲旺盛). Functions as an adjectival noun describing a state of abundance.
彼女は好奇心旺盛で、何にでも興味を持つ。
She is full of curiosity and takes an interest in everything.
うちの子は食欲旺盛で、よく食べる。
Our child has a hearty appetite and eats a lot.