Used to express surprise.
Origin of vumAlteration of vow 2 Our Living Language New Englanders sometimes express surprise by saying, “Well, I vum!” This odd-sounding word is in fact an alteration of the verb vow that goes back to the days of the American Revolution. It is also heard simply as “Vum!” or as a sort of past participle: “I'll be vummed!” A Southern equivalent is swan or swanny, also meaning “swear”: “Now, I swanny!” According to the Oxford English Dictionary, the word swanny derives from the dialect of the north of England: I s' wan ye, “I shall warrant ye” (that is, “I shall guarantee you”).
(third-person singular simple present vums, present participle vumming, simple past and past participle vummed)
- (US) An exclamation of surprise.
Alteration of vow.