convulsion

noun

1. An intense, paroxysmal, involuntary muscular contraction.

   “1850-1859, Charles Dickens, Household Words That immortal creature had gone over the proofs with great pains — had of course taken out the stiflings — hard-plungings, lungeings, and other convulsions — and had also taken out her weakenings and damagings of her own effects.”

2. An uncontrolled fit, as of laughter; a paroxysm.
3. Violent turmoil.

   “Earthquakes and convulsions of nature shake Earth on a regular basis.”

   “It would seem as if calm were necessary to convulsion; for the tranquillity of the last few months was again to be disturbed by political commotion.”

   “In a convulsion that has caught many in Brazil and beyond by surprise, waves of protesters denounced their leaders for dedicating so many resources to cultivating Brazil’s global image by building stadiums for international events, when basic services like education and health care remain woefully inadequate.”

4. Hysteric in nature.