Juvenile means involving a person too young to be treated as an adult. Juvenile crime, a juvenile court, a juvenile offender.
In law it is a category with real consequences: juvenile justice systems operate on different principles from adult ones, with more emphasis on rehabilitation. In biology, juvenile describes an animal not yet mature — a juvenile gull looks nothing like an adult one. The everyday sense is childish in a critical way: juvenile humour, do not be so juvenile. Note juvenile delinquent, which is now dated.
1adjectivejuvenileInvolving a person too young to be treated as an adult.
“The case went to a juvenile court and was dealt with in an hour.”
2adjectivechildishChildish, in a critical sense.
“The whole exchange was juvenile on both sides.”
juvenile is a stage of youth.
The Latin iuvenis is young, the same young behind junior. A juvenile is still too young to be tried as an adult.
hooks ontojunior
Latin iuvenilis comes from iuvenis, young — the same root as junior, juvenescent and, at a distance, young itself. The Latin and Germanic words for young are cousins from the same ancestor.
Proto-Indo-European
*h₂ey-
Proto-Indo-European
*h₂yuh₁en- — young
Latin
iuvenīlis — youthful; juvenile
English, today
juvenile
Built from
Borrowed from Latin iuvenīlis (“youthful; juvenile”), from iuvenis (“young; a youth”) + -īlis. Iuvenis is ultimately derived from Proto-Indo-European h₂yuh₁en- (“young”), from h₂óyu (“long life; lifetime”) (from h₂ey- (“age; life”)) + h₁én (“in”).
Etymology from Wiktionary, CC BY-SA