[in-fuhn-tahyl, -til]


characteristic of or befitting an infant; babyish; childish: infantile behavior.
of or relating to infants or infancy: infantile diseases.
Physical Geography. youthful(def 5).

Origin of infantile

From the Latin word infantīlis, dating back to 1690–1700. See infant, -ile
Related formsin·fan·til·i·ty [in-fuhn-til-i-tee] /ˌɪn fənˈtɪl ɪ ti/, noun

Synonyms for infantile

Synonym study

1. See childish.

Antonyms for infantile Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for infantile

childish, sophomoric, immature, juvenile, youthful

Examples from the Web for infantile

Contemporary Examples of infantile

Historical Examples of infantile

British Dictionary definitions for infantile



like a child in action or behaviour; childishly immature; puerile
of, relating to, or characteristic of infants or infancy
in an early stage of development
Derived Formsinfantility (ˌɪnfənˈtɪlɪtɪ), noun
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 infantile

mid-15c., "pertaining to infants," from Latin infantilis "pertaining to an infant," from infans (see infant). Sense of "infant-like" is from 1772.

Online Etymology Dictionary, © 2010 Douglas Harper

infantile in Medicine


[ĭnfən-tīl′, -tĭl]


Of or relating to infants or infancy.
Displaying or suggesting a lack of maturity; extremely childish.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.