con·vulse / kənˈvəls/ • v. [intr.] (of a person) suffer violent involuntary contraction of the muscles, producing contortion of the body or limbs. ∎  [tr.] (usu. be convulsed) (of an emotion, laughter, or physical stimulus) cause (someone) to make sudden, violent, uncontrollable movements: Carlos was convulsed by a second bout of sneezing. ∎  [tr.] fig. throw (a country) into violent social or political upheaval.

convulse XVII. f. convuls-, pp. stem of L. convellere pull violently, wrench, f. CON- + vellere pluck, pull.
So convulsion XVI. — F. or L.