Youthful; appearing or behaving as if young—looking younger than one's age or showing lively energy.
祖母は八十歳だがとても若々しい。
My grandmother is eighty, but very youthful.
彼女は若々しい声でスピーチを始めた。
She began the speech with a youthful-sounding voice.
若々しい服装をすることで印象が変わることがある。
Dressing youthfully can sometimes change one's impression.