feeble-mindedness
noun
fee·ble-mind·ed·ness ˌfē-bəl-ˈmīn-dəd-nəs 
variants or feeblemindedness
dated, offensive
: impairment in intellectual ability : intellectual disability
Note: The word feeble-mindedness, which is associated especially with eugenics practices of the late 19th and early 20th centuries, is no longer used in medical, educational, and regulatory contexts and is considered offensive.
Word History
First Known Use
1619, in the meaning defined above