From Latin pro Iuppiter. Ellipsis of a full oath of the form "I swear by Jupiter that…". Originally a literal oath; later a minced oath.
- (obsolete, Classics) Invocation of the Roman god Jupiter.
- 1820, Mitchell, Thomas, transl., “The Clouds”, in The Comedies of Aristophanes, volume 1, translation of Νεφέλαι Nephelai by Aristophanes, page 91:
- I see how it is with you. You are mad, / Stark mad, by Jupiter!
- (dated, chiefly British) Minced oath for by God.
- c. 1603–1606, Shakespeare, William, King Lear, act 1, scene 1, lines 178–179:
- Away! By Jupiter, / This shall not be revoked!
- 1874 September 1, Burnett, Fannie Hodgson, “Pretty Polly Pemberton”, in Peterson's Magazine, volume 66, number 3, page 180:
- "By Jupiter!" employing his usual mild expletive, "look here, old fellow, had she a white dress on, and geranium-colored bows, and—"
- See Thesaurus:wow or Thesaurus:dammit