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 (jo͞o′və-nīl′, -nəl)
a. Not fully grown or developed; young.
b. Of or characteristic of a young animal that has not reached sexual maturity: a bird still in juvenile plumage.
2. Characteristic of, intended for, or appropriate for children or young people: juvenile fashions.
3. Marked by immaturity; childish: juvenile behavior. See Synonyms at young.
4. Geology Relating to or being water, gas, or a mineral-rich fluid believed to have originated from magma and to have come to the earth's surface for the first time.
a. A young person; a child.
b. A young animal that has not reached sexual maturity.
c. A two-year-old racehorse.
2. An actor who plays roles of children or young persons.
3. A children's book.

[Latin iuvenīlis, from iuvenis, young; see yeu- in Indo-European roots.]

ju′ve·nile′ly adv.
ju′ve·nile′ness n.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
References in periodicals archive ?
Then, in Part III, this Note will discuss and analyze the issue of establishing a uniform constitutional definition of juvenileness that ends at eighteen years of age.
(95) The trend of changes in social science, psychology, cognitive science, and neuroscience, which now points to differences between juvenileness, adulthood, and a stage in between the two, supports the holdings of these three important cases and indicates the potential for further change.
The difference in cutoffs for juvenileness across the states presents problems.