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

In general, juvenile crimes are more often committed with others, and images of roaming throngs of teens has an outsized presence in media and in the public’s amygdala. —Eric Levenson, CNN Money, 9 May 2026

When officers arrived at the scene, a juvenile boy was being loaded into an ambulance. —Chelsea Hylton, CBS News, 8 May 2026

Noun

These changes enable researchers to distinguish juveniles, approximately 1-year-olds, and adults, making the baculum a useful tool for the understanding of raccoon age structure, a vital component of their management. —Sam Zeveloff, STAT, 9 May 2026

The investigation remains ongoing to determine whether additional criminal offenses occurred during the time the juvenile was missing. —Aaron A. Bedoya, USA Today, 8 May 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

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