Young or seeming young. / Characteristic of young people.

The vitality characteristic of youth.

In a youthful manner.

(geology) A fast-flowing river characterized by a deep, narrow erosion pattern forming a V-shaped channel or valley.

plural of youthfulness

plural of youthful river

(transitive) To make youthful.

Third-person singular simple present indicative form of youthfulize

simple past tense and past participle of youthfulize

present participle of youthfulize