immature

[im-uh-choor, -toor, -tyoor, -chur]

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

Synonyms for immature

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for immatureness

immature

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 (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

immature

adj.

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

immature

[ĭm′ə-chur, -tur]
adj.
  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.