Where did it come from? It resembles, at first glance, no other words we use regularly, even in academic settings, except “paradox.” The OED, as usual, has an answer. The word has Latin roots, but it came to English in the 16th Century via Old and Middle French, for the “onset of an illness.” Though I avoided COVID, right before the pandemic I got really ill: I’ll never forget the onset of symptoms of what seemed like influenza. I lay shaking abed with fever and chills.
If that’s not a term fit for the sudden onset of bad things, which is usually how we employ our word, I don’t know what else would quite fit. Our word can describe outbursts in nature, too: an Oklahoma tornado or the violent eruption of Mount St. Helens. That type of volcanic activity would, however, be the opposite of an ongoing and relatively gentler Strombolian eruption, using a word covered here before. The slow torture of human-caused climate change does not constitute a paroxysm, though individual weather events can.
The only positive use of the word that comes to mine would be a paroxysm of laughter. I hope we all have a few of those this summer with friends and family, after the grim months we all have endured.
If you have words or metaphors you would like covered, send them my way at jessid -at- richmond -dot- edu.
Image of Mount St. Helens blowing her top courtesy of Wikipedia.