(Scot and North England) disgusting, horrid; loathsome
In a sometimes ugsome, plague-filled world of violence and adventure that evokes the swashbuckling nature of The Count of Monte Cristo, you're presented with so many super heroic abilities, you feel like an omniscient kid in a candy store. (Harold Goldberg, 2012 In Review: The Best Games Of 2012, NPR, December 2012)
When doukin in the River Nile
I met a muckle crocodile.
He flicked his tail, he blinked his ee,
Syne bared his ugsome teeth at me.
At all events, the statute literally recites the 'ugsome oaths' that are used by the old versifier. (Julian Sharman. A Cursory History of Swearing)
I found my Vivien full sick, and a weariful and ugsome time had I with her ere she recovered of her malady. (Emily Sarah Holt, In Convent Walls)
1350–1400; Middle English, equivalent to ugg(en) to fear, cause loathing (Old Norse ugga to fear, dread; cf. Ugly) + -some-some (Dictionary.com)
If this reminds you of the inarticulate cry of disgust that most often appears as ugh! then you’re on the mark. The conventional spelling of ugh! was probably influenced by that of ugsome, something loathsome or horrible. In a case of linguistic turn-and-turn-about, ugsome derives from the ancient and long defunct word ug, which about a millennium ago came into English from the Old Norse ugga, to dread. That Old Norse word is also the source of ugly (which meant frightful or horrible before it weakened to refer to something merely unpleasing in appearance). You could argue that ugsome is the opposite of handsome.
In the centuries before Shakespeare, ugsome was common enough, mostly in Scotland and northern England, but then almost completely died out except in dialect. It was resurrected in the eighteenth century by writers seeking an archaic word to help set a historical scene. The following century, popular authors such as Sir Walter Scott (“Like an auld dog that trails its useless ugsome carcass into some bush or bracken”), Sir Edward Bulwer-Lytton (“‘’Tis an ugsome bit of road!’ said the Corporal, looking round him”) and Charles Dickens ('One very ugsome devil with goggling eyes, seems to hold up frightful claws, to bar the traveller’s way') regained it some small exposure, though it was never very popular. (World Wide Words)