ker-

• ka-, ca-, ke-, cha-

Now stands in for a thud. Originally Scots, possibly continuing^[1] Scottish Gaelic car (“somewhat”), cognate with Irish cor. Early uses were often collocated with went.^[2]

ker-

1. (often humorous) Used to form various onomatopoeias imitating the effect or sound of a heavy object falling.

   [The book] has suspense, pathos, bravery, and the bad guys get it in the end with a big KERWHAM! [2]

• RKE, erk