(n.) a nightmare; a period of haste or bustle
A widden-dream is a nightmare, while to do something in a widden-dream is to do it impetuously, hastily, or in a mindless hurry.
Etymologically, this is literally a ‘wooden’ dream—but not in the meaning that we’d know the word today.
Way back in the early Old English period, wood, as an adjective, meant mad or deranged; that’s a different word from wood in the sense of a forest or timber, of course, and you have to head even further back into the Germanic roots of English to pull the two apart. As an expanse of trees, wood was originally wudu, and through the Germanic language group is related to the likes of the German Wald (‘wood’), Swedish ved (‘tree’), and the English dialect wold (which lives on in place names today, like Stow-on-the-Wold).
As a word for a loss of sanity or mental balance, wood comes from a different root, wod, and has etymological cousins via the Germanic family of languages in the Welsh gwawd (a song of praise, in the sense of being overcome with inspiration), and even Odin (in the sense of being wild with rage) and ultimately Wednesday (which is quite literally ‘Odin’s day’).
Although wod, and eventually wood, in this sense has long since disappeared from English today, it nevertheless inspired the derivate widden-dream in the early Old English period to describe a nightmare or, more loosely, a frenzy situation. The term remains in use in a handful of dialects today.