わかわか若々wakawakaしいshii
1.
Exhibiting traits or characteristics that convey a sense of youthfulness and vitality, often associated with energy and freshness.
2.
Appearing noticeably younger than one's actual age, suggesting a vibrant and lively demeanor.
3.
Possessing an immaturity or naivety, sometimes reflecting a lack of experience or sophistication in behavior or outlook.
Example:
その年になってもまだ彼女は若々しい少女の面影を保っていた。