Noun
mild mental retardation
Source: WordNetThe habit of common and continuous speech is a symptom of mental deficiency. It proceeds from not knowing what is going on in other people's minds. Walter Bagehot
The habit of common and continuous speech is a symptom of mental deficiency. Walter Bagehot
After the war collaborationist behaviour was popularly viewed as a result of mental deficiency, leaving the personality of the clearly more intelligent Quisling an "enigma". Source: Internet
His book contained directions on how to use what he called "talk therapy", or Psychotherapy, to prompt an individual to reveal their deepest passions and secrets, and eventually cure them of their mental deficiency. Source: Internet
Reliability appears to be only satisfactory for three categories: mental deficiency, organic brain syndrome (but not its subtypes), and alcoholism. Source: Internet