Etymology From Middle English sethyng; equivalent to seethe + -ing.
1
Filled with unexpressed anger; in a state of being livid.
2
In a state of extreme volatility; about to boil over; boiling, bubbling.
There Grendel was watching his blood flow out into the seething tarn.1961, Norma Lorre Goodrich, “Beowulf”, in The Medieval Myths, New York: The New American Library, page 31:
But as the nation’s most populous state stares down a seething climate crisis, one that cranked temperatures into triple digits last fall and set off a series of infernos that exploded, into bone dry air, the rebuilding process is beginning to look different.2021 January 15, Debra Kamin, “Hounded by Wildfires, Californians Rethink Their Willingness to Rebuild”, in The New York Times, →ISSN:
3
In a state of unceasing and furious activity.
Otis was unfeignedly thankful to lay down his work for a little while and escape from the seething, whining, weakly hive, impotent to help itself, but strong in its power to cripple, thwart, and annoy the sunken-eyed man, who, by official irony, was said to be “in charge” of it.1889, Rudyard Kipling, “The Education of Otis Yeere”, in Under the Deodars, Boston: The Greenock Press, published 1899, page 29:
Etymology From Middle English sethyng; equivalent to seethe + -ing.
1
The action of the verb to seethe.
Over the winter-solid Roads, goes a great seething,— of mounted younger Gentlemen riding together by the dozens upon rented horses, Express Messengers in love with pure Velocity, Disgruntl'd Suitors with Pistols stuff'd in their Spatterdashes, seal'd Waggons not even a western Black-Boy would think of detaining.1997, Thomas Pynchon, chapter 39, in Mason & Dixon, 1st US edition, New York: Henry Holt and Company, →ISBN, part Two: America, page 395: