I’m sufficiently fond of Red Dwarf’s “Smeg” and “Smeghead” that, back in the 90s, I used to use it myself occasionally.
There’s a lot of swearing and cursing in scifi and fantasy books*, and authors love to make up realistic (or not) words for their characters, whether it’s “Light!” or “Peace!” from the Wheel of Time to the aforementioned “Smeg!” in RD.
Snut and Snuttin’, from foul-mouthed cigar-chewin’ whiskey-swillin’ wrench-hittin’ womanising-pilot-trapped-in-a-baby’s-body Jim Kidd in the old 2000AD strip Robo Hunter. John Wagner was banned from using it by the publisher because it sounded too filthy even for a fictional swear word.