backward+(undeveloped)adjective[UK: ˈbæk.wəd] [US: ˈbæk.wərd]
retarded+(delayed in development)adjective[UK: rɪ.ˈtɑː.dɪd] [US: rə.ˈtɑːr.dəd]
backward+adjective[UK: ˈbæk.wəd] [US: ˈbæk.wərd]
retarded+(having mental retardation)adjective[UK: rɪ.ˈtɑː.dɪd] [US: rə.ˈtɑːr.dəd]
↑