juggernaut (n.)

"an idea, custom, fashion, etc., that demands either blind devotion or merciless sacrifice," 1854, a figurative use of Juggernaut, 1630s (Iaggernat), "huge wagon bearing an image of the god Krishna," especially that at the town of Puri, drawn annually in procession during which (apocryphally) devotees allowed themselves to be crushed under its wheels in sacrifice. Altered from Jaggernaut, a title of Krishna (an incarnation of Vishnu), from Hindi Jagannath, literally "lord of the world."

This is from Sanskrit jagat "the world, men and beasts" (literally "the moving, all that moves," present participle of *jagati "he goes" (from PIE root *gwa- "to go, come") + natha-s "lord, master," from nathate "he helps, protects," from PIE root *nā- "to help." The first European description of the festival is by Friar Odoric (c. 1321).