Pronunciation: ( jOO'vu-nl, -nīl"),[key] —adj. 1. of, pertaining to, characteristic of, or suitable or intended for young persons: juvenile books. 2. young; youthful: juvenile years. 3. immature; childish; infantile: His juvenile tantrums are not in keeping with his age.
—n. 1. a young person; youth.
2. Theat. a. a youthful male or female role.
b. an actor or actress who plays such parts.
3. a book for children.
4. Ornith.a young bird in the stage when it has fledged, if altricial, or has replaced down of hatching, if precocial.
5. a two-year-old racehorse.