Moron was originally a scientific term, coined by psychologist Henry Goddard from a Greek word meaning "foolish" and used to describe a person with a genetically determined mental age between 8 and 12 on the Binet scale. It was also once applied to people with an IQ of 51-70 and was a step up from "imbecile" (IQ of 26-50) and two steps up from "idiot" (IQ of 0-25). The word moron, along with "retarded" and "feeble-minded" (among others), was once considered a valid descriptor in the psychological community, though these words have all now passed into common slang use, exclusively in a detrimental context.
