Some familiar words have etymologies right in front of us yet apt to stay hidden. Breakfast breaks a fast, the vowels disguising it well. Remorse is ‘biting back’, your conscience gnawing at you. Semicolon is a folk etymology of samey colon, on account of its resemblance to the other mark.
OK, I made that one up.
I read a nice account of another such etymology in Geoffrey Hughes’s Swearing: A Social History of Foul Language, Oaths and Profanities in English (1991). The book packs considerable detail, scholarly insight and amusing lists into its 280 pages, so I’ll follow its lead and keep this post short.1
In a section on ‘numinous words: charms, spells and runes’, Hughes writes:
One of the most dramatic instances of the use of a malign spell in Anglo-Saxon literature is wrought by the monster Grendel [in Beowulf].2 Described as one of the evil tribe of Cain and an enemy of the Lord, he puts a spell on the weapons of his victims, the Scyldings. The key verb in the text at this point is, fascinatingly, forsworen, literally ‘forsworn’, indicating that the verb forswerian could mean ‘to hinder by swearing; to render powerless by incantation; to make useless by magic’.
Hughes goes on to relate other examples of such word-magic from the Life of St Wilfrid and Bede’s Ecclesiastical History. Then he quotes from The Battle of Maldon and picks up the -swear- thread again:
Posted by Stan Carey 
Sentence first 