noun Date: 15th century an act or instance of retarding, the extent to which something is retarded, a musical suspension, 4. an abnormal slowness of thought or action, slowness in development or progress
RETARDATION
Meaning of RETARDATION in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012