by jingo

The story

1. Basque · borrowed fromJainkoa“god”
2. English todayby jingo

Uncertain for a long time. Main theories include: * a minced oath of "by Jesus"; compare crikey, zounds, egads, etc. * a corruption ultimately of "by St. Gingoulph", in reference to Saint Gangulphus of Burgundy. * a borrowing from Basque Jainkoa (“god”); compare by Jove. Basque sailors ― a common famous occupation for their people, who often swore by their term for God ― travelled far through the seas for centuries, and often met Englishmen.