Pronunciation: (yOOth'ful), [key]
1. characterized by youth; young.
2. of, pertaining to, or befitting youth: youthful enthusiasm.
3. having the appearance, freshness, vigor, etc., of youth: She is 60 but her optimism has kept her youthful.
4. in an early period of existence; early in time.
5. Physical Geog.(of topographical features) having undergone erosion to a slight extent only.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.