<unk>  (DDK) is the medical term for an impaired ability to perform rapid, alternating movements (i.e., diadochokinesia). Complete inability is called adiadochokinesia. The term is from Greek δυς dys "bad", διάδοχος diadochos "succeeding", κίνησις kinesis "movement".
Dysdiadochokinesia
Diadochokinesia
Hypokinesia
Adiadochokinesia
Xanthochromia
Chromoplexy
Aniridia
Hyperspermia