youthfulness
youth·ful·ness
noun
1.
the freshness and vitality characteristic of a young person
Origin
From youthful + -ness.
Related words
Broader terms
WordNet 2.1 (Princeton University). Wiktionary (CC BY-SA). WordNet 2.1 Copyright Princeton University. All rights reserved. Wiktionary content is available under the Creative Commons Attribution-ShareAlike Licence.