a poor ability to understand or to profit from experience

slow the growth or development of

retardation sufficient to fall outside the normal range of intelligence

mild mental retardation

extreme mental retardation

retardation more severe than a moron but not as severe as an idiot

A condition in which a person with a mental disability, such as an autism spectrum disorder, demonstrates profound and prodigious capacities or abilities far in excess of what would be considered normal.