Displaying or suggesting a lack of maturity; childish: infantile behavior; an infantile remark. (adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "infantile" in a sentence
"He said, "I state my belief that the precipitating factor in infantile autism is the parents wish that the child should not exist.""
"Anytime they post and insult, and then respond to someone poking fun at them by calling the person infantile, is too good a chance to pass up."
"Saying that it's God's fault he's infantile is just taking a cheap shot because it takes responsibility away from Adam - you ate the apple."