tic
n. a sudden, involuntary vocalization (vocal tic) or contraction of a small group of muscles (motor tic) that is recurrent and nonrhythmic. Tics may be simple (e.g., eye blinking, shoulder shrugging, grimacing, throat clearing, grunting, yelping) or complex (e.g., hand gestures, touching, jumping, echolalia, coprolalia). They may be psychogenic in origin, or they may occur as an adverse effect of a medication or other substance or result from a head injury, neurological disorder, or general medical condition.