re·tar·da·tion 
/ˌri:ˌtɑɚˈdeɪʃən/ noun
/ˌri:ˌtɑɚˈdeɪʃən/ noun [noncount] 1 old-fashioned + sometimes offensive : an unusual slowness of mental development
▪ The child suffered severe mental retardation. 2 formal : an act of slowing down the development or progress of something
▪ The chemical induced a retardation of cell growth.
▪ The child suffered severe mental retardation.
▪ The chemical induced a retardation of cell growth.
