convulsion in WordNet English dictionary

1. a physical disturbance such as an earthquake or upheaval
   convulsion 
   
2. violent uncontrollable contractions of muscles
   convulsion 
   
3. a sudden uncontrollable attack
   "a paroxysm of giggling"; "a fit of coughing"; "convulsions of laughter"
   paroxysm  fit  convulsion 
   
4. a violent disturbance
   "the convulsions of the stock market"
   convulsion  turmoil  upheaval