convulsion definition
- Full Definition of CONVULSION. 1. : an abnormal violent and involuntary contraction or series of contractions of the muscles. 2. a: a violent disturbance b: an uncontrolled fit: paroxysm. â conÂ·vulÂ·sionÂ·ary \-shÉ-Ëner-Ä\ adjective.See convulsion defined for English-language learners. See convulsion defined for kids.edical: a sudden violent shaking of the muscles in your body that you are unable to control. : a sudden experience of something (such as laughter) that shakes or moves your body.