convulsive (adj.)

1610s, "of the nature of or characterized by convulsion," from French convulsif, from Medieval Latin *convulsivus, from convuls-, past-participle stem of convellere "to pull away, to pull this way and that, wrench," from assimilated form of com "with, together" (see con-) + vellere "to pluck, pull violently" (see svelte). Meaning "producing or attended by convulsions" is from 1700. Related: Convulsively.