Imbecile is a term for moderate to severe mental retardation, as well as for a type of criminal. It arises from the Latin word imbecillus, meaning weak, or weak-minded. "Imbecile" was once applied to people with an IQ of 26-50, between "moron

Moron (psychology)

Moron is a term once used in psychology to denote mild mental retardation. The term was closely tied with the American eugenics movement. Once the term became popularized, it fell out of use by the psychological community, as it was used more commonly as an insult than as a psychological...

" (IQ of 51-70) and "idiot" (IQ of 0-25).

The term was further refined into mental and moral imbecility. The concepts of "moral insanity," "moral idiocy," and "moral imbecility," led to the emerging field of eugenic criminology, which held that crime can be reduced by preventing "feeble-minded

Feeble-minded

The term feeble-minded was used from the late nineteenth century in Great Britain, Europe and the United States to refer to a specific type of "mental deficiency". At the time, mental deficiency was an umbrella term, which encompassed all degrees of educational and social deficiency...

" people from reproducing.

"Imbecile" as a concrete classification was popularized by psychologist

Psychologist

Psychologist is a professional or academic title used by individuals who are either:* Clinical professionals who work with patients in a variety of therapeutic contexts .* Scientists conducting psychological research or teaching psychology in a college...

 Henry H. Goddard

Henry H. Goddard

Henry Herbert Goddard was a prominent American psychologist and eugenicist in the early 20th century...

 and was used in 1927 by United States Supreme Court

Supreme Court of the United States

The Supreme Court of the United States is the highest court in the United States. It has ultimate appellate jurisdiction over all state and federal courts, and original jurisdiction over a small range of cases...

 Justice Oliver Wendell Holmes, Jr.

Oliver Wendell Holmes, Jr.

Oliver Wendell Holmes, Jr. was an American jurist who served as an Associate Justice of the Supreme Court of the United States from 1902 to 1932...

 in his landmark ruling in the forced-sterilization case Buck v. Bell

Buck v. Bell

Buck v. Bell, , was the United States Supreme Court ruling that upheld a statute instituting compulsory sterilization of the unfit, including the mentally retarded, "for the protection and health of the state." It was largely seen as an endorsement of negative eugenics—the attempt to improve...

.

The term is closely associated with psychology

Psychology

Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...

, psychiatry

Psychiatry

Psychiatry is the medical specialty devoted to the study and treatment of mental disorders. These mental disorders include various affective, behavioural, cognitive and perceptual abnormalities...

, criminology

Criminology

Criminology is the scientific study of the nature, extent, causes, and control of criminal behavior in both the individual and in society...

, and eugenics

Eugenics

Eugenics is the "applied science or the bio-social movement which advocates the use of practices aimed at improving the genetic composition of a population", usually referring to human populations. The origins of the concept of eugenics began with certain interpretations of Mendelian inheritance,...

. The term imbecile quickly passed into vernacular usage as a derogatory term, and fell out of professional use in the 20th century.