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REFERENCE

immature

adj. · n.
US //ˌɪmətˈjʊɹ// UK //ˌɪmətʃˈɔː// im·ma·ture
  1. 1 childish behavior (adj.)
    B2 Upper Intermediate

    acting in a way that is silly or childish, especially for your age.

    exhibiting psychological or social behavior inappropriate for one's chronological age; puerile.

    Example

    It was very immature of him to start shouting just because he lost the game.

    Example

    The manager's immature response to constructive criticism created a toxic atmosphere within the department, as he often resorted to personal insults during meetings.
  2. 2 not fully grown (adj.)
    B2 Upper Intermediate Science

    not yet fully developed or grown.

    not having reached a state of full development or reproductive maturity.

    Example

    The immature birds still have gray feathers and cannot fly long distances yet.

    Example

    The biologist noted that the immature specimens lacked the distinctive markings found on adults of the same species.
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  1. 3 happening too early (adj.)
    C2 Proficiency Archaic

    happening before the right or expected time.

    occurring before the natural or proper time; premature.

    Example

    The poet wrote a sad poem about the immature death of a young soldier.

    Example

    In the nineteenth-century novel, the protagonist laments the immature end of his political career following the scandal.
  2. 4 a young animal (n.)
    C1 Advanced Technical Science

    an animal or plant that is not yet an adult.

    an individual organism that has not yet reached sexual maturity or its final adult form.

    Example

    The researchers counted twelve immatures among the group of seals on the beach.

    Example

    Distinguishing between immatures and females of this particular butterfly species requires careful examination of the wing patterns under a microscope.
Origin

From Middle French immature. Partially displaced unripe, from Old English unrīpe (“unripe, immature”).

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