Involuntary muscle movement is a type of movement that occurs without conscious control. It can be caused by a variety of conditions, such as neurological disorders, trauma, or even stress. Two common terms used to describe involuntary muscle movement are TIC (3 letters) and SPASM (5 letters). TIC stands for 'transient ischemic contraction' and is a brief, involuntary contraction of a muscle or group of muscles. SPASM is an abrupt, involuntary contraction of a muscle or group of muscles. Both of these terms refer to the same type of involuntary muscle movement.