'Youthfully' definitions:

Definition of 'youthfully'

(from WordNet)
adverb
In a youthful manner; "he is still youthfully enthusiastic"

Definition of 'Youthfully'

From: GCIDE
  • Youthful \Youth"ful\, a.
  • 1. Not yet mature or aged; young. "Two youthful knights." --Dryden. Also used figuratively. "The youthful season of the year." --Shak. [1913 Webster]
  • 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. [1913 Webster]
  • 3. Fresh; vigorous, as in youth. [1913 Webster]
  • After millions of millions of ages . . . still youthful and flourishing. --Bentley. [1913 Webster]
  • Syn: Puerile; juvenile.
  • Usage: 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. [1913 Webster] -- {Youth"ful*ly}, adv. -- {Youth"ful*ness}, n. [1913 Webster]