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.
That person is a moron!
by zippy_little_thing May 30, 2006
 Get the Moronmug.
Get the Moronmug. i don't have a definition, i just thought it was funny that the second definition uses the word "stupider" to describe someone who is a moron.
by pseudonymjones0 December 6, 2004
 Get the moronmug.
Get the moronmug. by Ryan Dawson February 6, 2006
 Get the moronitymug.
Get the moronitymug. Someone who, in submitting an urban dictionary entry, doesn't quite get the concept that you are trying to define something, not make an argument in favor of it or write a commercial for it.
by Christopher Olsen November 1, 2006
 Get the moronmug.
Get the moronmug. by Anyomonous123 February 14, 2008
 Get the moronmug.
Get the moronmug. A person who is lacking intellectual capacity and general common sense. 
This slang word is mostly used in a derogatory sense.
This slang word is mostly used in a derogatory sense.
by YC7 June 24, 2008
 Get the Moronmug.
Get the Moronmug.