adj.
- Of or relating to infants or infancy.
- Displaying or suggesting a lack of maturity; childish: infantile behavior; an infantile remark.
[Middle English infantil, from Latin īnfantīlis, from īnfāns, īnfant-, infant. See infant.]
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.