Boland is an immature kid with a lean, unsmiling face, ice-blue eyes, and wavy blond hair.
Margene has often seemed the most immature of Bill's three wives, little more than a child herself.
When she arrived, she found a fraternity full of immature and sexually inappropriate behavior.
Americans are terrified of death, and often demonstrate an immature refusal to accept it.
For a time he had a crush on a girl in our class who thought he was an immature goofball.
The most immature essay must be more than a summary; a mere summary is never an essay.
Was this the child-like, immature being of their strange visit to Miraflores?
A man is bound above all things to protect those who depend on him from his own immature or revocable impulses.
The present experience, he decided, was immature, a mere coincidence.
The Oriental mind is an old, old mind, richly stored with experience and memories,—not in the least gullible and immature.
1540s, "untimely, premature," from Latin immaturus "untimely, unripe," from assimilated form of in- "not, opposite of" (see in- (1)) + maturus (see mature (v.)). In 16c., usually in reference to early death; modern sense of "not fully developed" first recorded 1640s. In reference to mentalities or behaviors not considered age-appropriate, from 1920.
immature im·ma·ture (ĭm'ə-tyur', -tur', -chur')
Not fully grown or developed.