immature

adjective

im·​ma·​ture ˌi-mə-ˈchu̇r  -ˈtu̇r 

-ˈtyu̇r

1

a

: exhibiting less than an expected degree of maturity

emotionally immature adults

b

: lacking complete growth, differentiation, or development

immature fruits

a sexually immature bird

c

: having the potential capacity to attain a definitive form or state : crude, unfinished

a vigorous but immature school of art

2

archaic : premature

immature noun

immaturely adverb

immaturity

ˌi-mə-ˈchu̇r-ə-tē 

-ˈtu̇r-

-ˈtyu̇r-

noun

Synonyms

• adolescent
• juvenile
• young
• youngish
• youthful

Examples of immature in a Sentence

The flock included both adult and immature birds.

His teachers have complained about his immature behavior.

Recent Examples on the Web

This doesn’t sound like their mess to clean up, and just sounds a bit immature/entitled. —Latoya Gayle, People.com, 26 Apr. 2025

Children and adults pick up an avalanche of unreliable information on social media, and children may process it with immature judgment. —Sun Sentinel Editorial Board, Sun Sentinel, 22 Apr. 2025

Yet that flies in the face of the basis for the bill — the substantial evidence documenting that the brains of young people are immature and thus unable to control their impulses. —Robert Barton, Baltimore Sun, 13 Apr. 2025

The treatment was derived from human embryonic stem cells, which researchers had coaxed into becoming immature brain cells called neuron progenitors. —Jon Hamilton, NPR, 17 Apr. 2025

Word History

Etymology

Latin immaturus, from in- + maturus mature

First Known Use

1548, in the meaning defined at sense 2

Rhymes for immature

• annexure
• embouchure
• epicure
• paramour
• premature
• reassure
• reinsure
• sinecure
• abjure
• adjure
• allure
• assure

Kids Definition

immature

adjective

im·​ma·​ture ˌim-ə-ˈt(y)u̇(ə)r 

1

: not mature or fully developed : young, unripe

an immature bird

immature fruit

2

: showing less than an expected degree of maturity

immature behavior

immaturely adverb

Medical Definition

immature

adjective

im·​ma·​ture

ˌim-ə-ˈt(y)u̇(ə)r also -ˈchu̇(ə)r

: lacking complete growth, differentiation, or development

immature blood cells

emotionally immature

immaturely adverb

immaturity

-ˈt(y)u̇r-ət-ē also -ˈchu̇r-

noun

plural immaturities