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

• young
• juvenile

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

When the eggs hatch, the immature stages start feeding. —Arricca Elin Sansone, Southern Living, 5 Aug. 2025

Why is the administration favoring advanced nuclear and next-gen geothermal which are commercially immature compared with wind and solar? —Ian Dexter Palmer, Forbes.com, 4 Aug. 2025

That’s the idea of being mature or immature, right? —Jason Jones, New York Times, 1 Aug. 2025

At the very worst, an immature 18-year-old makes a horrific decision on a whim to deface his or her torso with a tableau of repulsive images that could potentially cause medical complications later in life. —Scott Liftman, Boston Herald, 25 July 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