ferment

Etymology

From Middle English ferment, from Middle French ferment, from Latin fermentāre (“to leaven, ferment”), from fermentum (“substance causing fermentation”), from fervēre (“to boil, seethe”). See also fervent.

verb

1. To react, using fermentation; especially to produce alcohol by aging or by allowing yeast to act on sugars; to brew.
   The cleanup job would turn out to be possibly second only to body-recovery duty in terms of being a job that nobody wanted to get assigned to. Imagine, for a moment, a thick soup of oil, paper, ink, clothing, raw meat and other fresh provisions, and worse, that had all been left to collect together in semi-warm water, all enclosed in a large metal container that had then been subjected to heating by first fire and then repeated warm Hawaiian days, and then left to ferment for over a month, and then with most of the water drained away and all the remaining solid and semi-liquid mass collecting together in pools and heaps across multiple decks, still in a relatively-enclosed environment. 18 November 2020, Drachinifel, 6:21 from the start, in The Salvage of Pearl Harbor Pt 2 - Up She Rises!, archived from the original on 2022-10-22
2. To stir up, agitate, cause unrest or excitement in.

noun

1. Something, such as a yeast or barm, that causes fermentation.
2. A state of agitation or of turbulent change.
   Subdue and cool the ferment of desire. a. 1729, John Rogers, The Difficulties of Obtaining Salvation
   14 November, 1770, Junius, letter to the Right Honourable Lord Mansfield The nation is in a ferment.
   Clad in a Persian-Renaissance gown and a widow's tiara of white batiste, Mrs Thoroughfare, in all the ferment of a Marriage-Christening, left her chamber on vapoury autumn day and descending a few stairs, and climbing a few others, knocked a trifle brusquely at her son's wife's door. 1919, Ronald Firbank, Valmouth, Duckworth, hardback edition, page 104
3. A gentle internal motion of the constituent parts of a fluid; fermentation.
4. A catalyst.