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immature

American  
[im-uh-choor, -toor, -tyoor, -chur] / ˈɪm əˈtʃʊər, -ˈtʊər, -ˈtyʊər, -ˈtʃɜr /

adjective

  1. not mature, ripe, developed, perfected, etc.

  2. emotionally undeveloped; juvenile; childish.

    Synonyms:
    babyish, puerile, callow
  3. Physical Geography. youthful.

  4. Archaic. premature.


immature British  
/ -ˈtʃʊə, ˌɪməˈtjʊə /

adjective

  1. not fully grown or developed

  2. deficient in maturity; lacking wisdom, insight, emotional stability, etc

  3. geography a less common term for youthful

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Derived Forms

Etymology

Origin of immature

First recorded in 1540–50, immature is from the Latin word immātūrus unripe, hence, untimely. See im- 2, mature

Explanation

Use the adjective immature to describe something that is not fully grown: “Elizabeth rescued an immature sparrow that had fallen from its nest during the storm.” When used in a general sense, immature describes something in an early stage of development, such as an immature fruit tree or an immature political system. When applied to people, however, immature is often used to describe someone who behaves in a childish way. So if your 42-year-old brother spends the entire holiday weekend playing video games and then throws a temper tantrum when you ask him to help with the dishes, the word you’re looking for to describe him is probably immature.

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Vocabulary lists containing immature

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Dr Ernesto Maceira, a specialist who treated the Spaniard's foot, said the condition was caused by "abnormal forces that act on an immature bone" and attributed it to Nadal's intense training as a child.

From BBC • May 29, 2026

Large language models are an immature technology, and engineering improvements for specialized data centers should be expected—but how big they are and when they come is unknowable in advance.

From The Wall Street Journal • May 17, 2026

It contains millions of "silent synapses," which are immature connections between neurons that remain inactive until they are needed to help form new memories.

From Science Daily • May 6, 2026

The Army itself advises soldiers to “maintain the high ground,” and research shows that rapid-fire calls made under pressure by the morally immature lead to disaster.

From Slate • Apr. 13, 2026

Had the rider given Blume a moment to consider the risk Pollard was taking in riding an immature colt just before a major race, Blume would not have let him go.

From "Seabiscuit: An American Legend" by Laura Hillenbrand

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