[n] violent uncontrollable contractions of muscles
\Con*vul"sion\, n. [L. convulsio: cf. F. convulsion.]
1. (Med.) An unnatural, violent, and unvoluntary contraction of the muscular parts of an animal body.
2. Any violent and irregular motion or agitation; a violent shaking; a tumult; a commotion. Those two massy pillars, With horrible convulsion, to and fro He tugged, he shook, till down they came. --Milton. Times of violence and convulsion. --Ames. Syn: Agitation; commotion; tumult; disturbance.