Originally, unfortunate people of below-average intelligence were called "mentally deficient", but people started using that as an insult so they changed it to "mentally retarded" which became even more of an insult. The latest term now is "developmentally delayed". Just to show those politically correct retards that changing the word does jack s**t, let's use "delayed" as the new insult...
btw don't actually hate on clinically stupid people they don't really deserve it, its just fun to make up insults
"are you f**king delayed?"
"stop acting so delayed!"
"why are you being so f**king delayed in the head?"
"that was really delayed of you!"