YOUTHFUL
youthful, vernal, young
(adjective) suggestive of youth; vigorous and fresh; “he is young for his age”
Source: WordNet® 3.1
Etymology
Adjective
youthful (comparative more youthful, superlative most youthful)
Young or seeming young.
Synonyms: lively, sprightly, spry, young, Thesaurus:young, Thesaurus:active
Characteristic of young people.
Source: Wiktionary
Youth"ful, a.
1. Not yet mature or aged; young. "Two youthful knights." Dryden.
Definition: Also used figuratively. "The youthful season of the year."
Shak.
2. Of or pertaining to the early part of life; suitable to early
life; as, youthful days; youthful sports. "Warm, youthful blood."
Shak. "Youthful thoughts." Milton.
3. Fresh; vigorous, as in youth.
After millions of millions of ages . . . still youthful and
flourishing. Bentley.
Syn.
– Puerile; juvenile.
– Youthful, Puerile, Juvenile. Puerile is always used in a bad
sense, or at least in the sense of what is suitable to a boy only;
as, puerile objections, puerile amusements, etc. Juvenile is
sometimes taken in a bad sense, as when speaking of youth in contrast
with manhood; as, juvenile tricks; a juvenile performance. Youthful
is commonly employed in a good sense; as, youthful aspirations; or at
least by way of extenuating; as, youthful indiscretions. "Some men,
imagining themselves possessed with a divine fury, often fall into
toys and trifles, which are only puerilities." Dryden. "Raw, juvenile
writers imagine that, by pouring forth figures often, they render
their compositions warm and animated." Blair.
– Youth"ful*ly, adv.
– Youth"ful*ness, n.
Source: Webster’s Unabridged Dictionary 1913 Edition