morbleu
/mɔːˈbləː/(also marblue) Chiefly humorous
exclamation
Expressing annoyance, surprise, etc. (usually attributed to French speakers).
Origin
Mid 17th century; earliest use found in George Etherege (1636–1691), playwright and diplomat. From French morbleu (1664 in Molière; an altered form of mort Dieu, after bleu blue noun; compare Middle French morbieu).