A leather scourge (multi-tail whip), in the severe version known as 'great knout' with metal weights on each tongue, notoriously used in imperial Russia.

“1980: Spray and then slogging knouts of water hit the windows or lights like snarling disaffected at a mansion of the rich and frivolous. — Anthony Burgess, Earthly Powers”

To flog or beat with a knout.