• synonyms


[im-uh-choo r, -too r, -tyoo r, -chur]
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  1. not mature, ripe, developed, perfected, etc.
  2. emotionally undeveloped; juvenile; childish.
  3. Physical Geography. youthful(def 5).
  4. Archaic. premature.

Origin of immature

First recorded in 1540–50, immature is from the Latin word immātūrus unripe, hence, untimely. See im-2, mature
Related formsim·ma·ture·ly, adverbim·ma·ture·ness, noun


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2. callow, puerile, babyish.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for immatureness


  1. not fully grown or developed
  2. deficient in maturity; lacking wisdom, insight, emotional stability, etc
  3. geography a less common term for youthful (def. 4)
Derived Formsimmaturity or immatureness, nounimmaturely, adverb
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

Word Origin and History for immatureness



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.

Online Etymology Dictionary, © 2010 Douglas Harper

immatureness in Medicine


(ĭm′ə-chur, -tur)
  1. Not fully grown or developed.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.