Literally, dyskinesia means difficulty in performing voluntary movement, such as lifting an arm or nodding the head. (In contrast, movements such as eyeblinks or reflex responses are considered involuntary, since they occur without conscious intent.)

Patients experiencing dyskinesia may have trouble initiating movements, including the motor movements of mouth and larynx needed for speaking and the facial movements needed to display facial expression.

Dyskinesia is a symptom of Parkinson's disease and other motor disorders.