#mental_retardation__retardation__backwardness__slowness__subnormality  lack of normal development of intellectual capacities
  supertype:  stupidity  a poor ability to understand or to profit from experience
  subtype:  mental_defectiveness__abnormality  retardation sufficient to fall outside the normal range of intelligence
     subtype:  feeblemindedness  severe mental deficiency
  subtype:  moronity__mental_deficiency  mild mental retardation
  subtype:  idiocy__amentia  extreme mental retardation
  subtype:  imbecility  retardation more severe than a moron but not as severe as an idiot

No statement uses or specializes mental_retardation; click here to add one.