blunderbuss (n.)

"short, large-bore gun or firearm with a funnel-shaped muzzle," 1650s, from Dutch donderbus, from donder "thunder" (Middle Dutch doner, donder, from Proto-Germanic *thunaraz; see thunder (n.)) + bus "gun" (originally "box, tube"); altered by resemblance to blunder. Related: Blunderbussier.