juvenile

1 of 2

adjective

ju·​ve·​nile ˈjü-və-ˌnī(-ə)l  -nᵊl 

1

: physiologically immature or undeveloped : young

juvenile birds

2

a

: of, relating to, characteristic of, or suitable for children or young people

juvenile fiction

b

: of or relating to young people who have committed or are accused of committing a criminal offense

the juvenile justice system

juvenile crime

3

: reflecting psychological or intellectual immaturity : childish

juvenile behavior

juvenile pranks

told him he was being juvenile

4

: derived from sources within the earth and coming to the surface for the first time

—used especially of water and gas

juvenile

2 of 2

noun

plural juveniles

1

a

: a young person : youth

often, specifically : an individual who is under an age fixed by law (such as 18 years) at which a person would be charged as an adult for a criminal act

… some states also have been changing their laws to give school administrators more access to the records of juveniles whose cases were processed by juvenile courts.

—Peter Schmidt

b

: a book for children or young people

2

: a young individual resembling an adult of its kind except in size and reproductive activity: such as

a

: a fledged bird not yet in adult plumage

b

: a 2-year-old racehorse

3

: an actor or actress who plays youthful parts

Synonyms of juvenile

Adjective

• young
• immature

Noun

• kid
• child

Examples of juvenile in a Sentence

Adjective

She criticized his juvenile behavior at the party.

a juvenile alligator just hatched from its egg

Noun

She works to keep juveniles away from drugs.

a medical study that followed juveniles through adolescence and into adulthood

Recent Examples on the Web

Adjective

One 16-year-old suspect was transported to a juvenile detention center, while the four adults were taken to the Frederick County Adult Detention Center. — CBS News, 7 Oct. 2026

They were transported to a juvenile detention facility, officers said. — Camryn Dadey, Sacbee.com, 6 Oct. 2026

Noun

In the livers of urban fish, 425 genes in juveniles and 585 in adults showed activity largely linked to inflammation and immune system responses that was not seen in damselfish living in clean, untouched reef areas. — New Atlas, 9 Oct. 2026

The report did not name the juvenile or disclose any information about their connection to Brown. — Justin Muszynski, Hartford Courant, 3 Oct. 2026

Word History

Etymology

Adjective

French or Latin; French juvénile, from Latin juvenilis, from juvenis young person — more at young

First Known Use

Adjective

1625, in the meaning defined at sense 1

Noun

1733, in the meaning defined at sense 1a

Phrases Containing juvenile

• juvenile court
• juvenile delinquency
• juvenile diabetes
• juvenile hormone
• juvenile officer
• juvenile-onset diabetes

Kids Definition

juvenile

1 of 2 adjective

ju·​ve·​nile ˈjü-və-ˌnīl  -vən-ᵊl 

1

: showing incomplete development : immature, childish

2

: of, relating to, or characteristic of children or young people

juvenility

ˌjü-və-ˈnil-ət-ē

noun

juvenile

2 of 2 noun

1

: a young person, animal, or plant

2

: a book for young people

3

: an actor who plays youthful parts

Medical Definition

juvenile

1 of 2 adjective

ju·​ve·​nile ˈjü-və-ˌnīl  -vən-ᵊl 

1

: physiologically immature or undeveloped

juvenile fish

2

: of, relating to, characteristic of, or affecting children or young people

juvenile arthritis

3

: reflecting psychological or intellectual immaturity

juvenile behavior

juvenile

2 of 2 noun

1

: a young person

especially : one below the legally established age (as of 18) of adulthood

2

: a young individual resembling an adult of its kind except in size and reproductive activity

Legal Definition

juvenile

noun

ju·​ve·​nile

ˈjü-və-ˌnīl, -nəl

: an individual who is under an age fixed by law (as 18 years) at which he or she would be charged as an adult for a criminal act compare minor