Synonyms for Youthful:

adj.

adolescent (adjective)
teenage, immature, adolescent, pubescent, puerile, juvenile.
babyish (adjective)
infantile.
green (adjective)
green.
juvenile (adjective)
junior, immature, childish, juvenile, adolescent, infantile, young.
new, immature (adjective)
enthusiastic, inexperienced, adolescent, boyish, girlish, juvenile, childish, callow, young, buoyant, infant, keen, vigorous, puerile, active, childlike, pubescent, green, vernal, fresh.
springlike (adjective)
vernal.
young (adjective)
fresh, unripe, childish, inexperienced, junior, teenage, callow, boyish, juvenile, immature, child-like, young, puerile, blooming, girlish, adolescent, pubescent, green.

n.

active, youth culture, childlike. full-blooded, lighthearted, athletic, keen, slow, limber, enthusiastic, prankish, vigorous, lithe, buoyant, cautious. infant, youth. youthful (noun)
immature, young, vernal.

Other synonyms:

youth culture. youth. infant. Other relevant words:
infant, limber, active, keen, vigorous, lithe, enthusiastic, vernal, youth, prankish, buoyant, childlike.

Usage examples for youthful

  1. Bricriu Meets Cuchulain " May all good be with you, Cuchulain," said Bricriu, as he met the youthful hero. – Hero-Myths & Legends of the British Race by Maud Isabel Ebbutt
  2. Such was the simple faith of youthful friendship. – Susy, A Story of the Plains by Bret Harte
  3. But she had lost her father, the object of her greatest, her only youthful affection; then she had married. – Fromont and Risler, Complete by Alphonse Daudet Last Updated: March 3, 2009