5 Answers

Slowing something down, the act of slowing something down.  A person can be born with retardation or you can retard an act……….

Intellectual disability (ID) or general learning disability is a generalized disorder appearing before adulthood, characterized by significantly impaired cognitive functioning and deficits in two or more adaptive behaviors. Intellectual disability is also known asmental retardation.

Source > http://en.wikipedia.org/wiki/Mental_retardation

Many babies with Thyroid deficiencies which go untreated do not develop and become retarded, physically and mentally.  Thank God that they test babies with blood work today, it saved my grandson who is on meds for Hypothyroidism and is advancing well. 

Getting your spark plugs to fire before Top-Dead-Centre,

the inability of politicians and leaders, all around the world, to communicate for the betterment of societies. they'd rather fight and kill each other.  that's retarded.  animals are not as retarded.