Paroxysm is defined as a fit, attack, or sudden increase or recurrence of symptoms (as of a disease), seizure or spasm. There is also a second definition of the word: a sudden violent emotion or action.

Synonyms of paroxysm are: convulsion, outburst, frenzy, agitation.

Here is an example of using the word in a sentence: The rowdy crowd fell into a paroxysm of despair and rage upon their team's loss in the title game.

More Info: www.merriam-webster.com