juvenile

American Heritage® Dictionary of the English Language, Fourth Edition

1. adj. Not fully grown or developed; young.
2. adj. Of, relating to, characteristic of, intended for, or appropriate for children or young people: juvenile fashions.
3. adj. Marked by immaturity; childish: juvenile behavior. See Synonyms at young.
4. n. A young person; a child.
5. n. A young animal that has not reached sexual maturity.
6. n. An actor who plays roles of children or young persons.
7. n. A children's book.

Century Dictionary and Cyclopedia

1. Young; youthful: as, a juvenile manner; a juvenile part in a play.
2. Pertaining or suited to youth: as, juvenile sports or books.
3. Synonyms Boyish, Puerile, etc. See youthful.
4. n. A young person; a youth.
5. n. A book written for young persons or children.
6. n. Theat., an actor who plays youthful parts: as, a first juvenile.

Wiktionary

1. adj. young; not fully developed
2. adj. characteristic of youth or immaturity; childish
3. n. a prepubescent child
4. n. a person not legally of age, or who is younger than may be charged with an offence
5. n. an animal that is not sexually mature
6. n. an actor playing a child's role

GNU Webster's 1913

1. adj. Young; youthful.
2. adj. Of or pertaining to youth.
3. adj. Characteristic of children; immature; childish; puerile; infantile.
4. n. A young person or youth; -- used sportively or familiarly.

WordNet 3.0

1. n. a young person, not fully developed
2. adj. displaying or suggesting a lack of maturity
3. adj. of or relating to or characteristic of or appropriate for children or young people