Noun | 1. | hyperactivity - a condition characterized by excessive restlessness and movement disorder, upset - a physical condition in which there is a disturbance of normal functioning; "the doctor prescribed some medicine for the disorder"; "everyone gets stomach upsets from time to time" ADD, ADHD, attention deficit disorder, attention deficit hyperactivity disorder, hyperkinetic syndrome, MBD, minimal brain damage, minimal brain dysfunction - a condition (mostly in boys) characterized by behavioral and learning disorders |