im·be·cile (ĭmbə-sĭl, -səl)
1. A person who is considered foolish or stupid.
2. A person with moderate to severe intellectual disability having a mental age of from three to seven years and generally being capable of some degree of communication and performance of simple tasks under supervision. The term belongs to a classification system no longer in use and is now considered offensive.
[From obsolete French imbécille, weak, feeble, from Old French, from Latin imbēcillus : in-, not; see IN-1 + possibly bacillum, staff, diminutive of baculum, rod; see bak- in the Appendix of Indo-European roots.]
im′be·cilic (-sĭlĭk) adj.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.