Английский Этимологический словарь - cucking stool

- M.E., from cuck "to void excrement," from O.N. kuka "feces" (the chair was sometimes in the form of a close-stool). Also known as trebucket and castigatory, it was used on disorderly women and fraudulent tradesmen, either in the form of public exposure to ridicule or for ducking in a pond.