means A flexible lash or rod used to strike, drive animals, or—by extension—to compel, urge on, or enforce discipline (as the party 'whip' in politics does to keep members in line).

from From Middle English 'wippen,' meaning to move quickly or strike with a flick—related to Middle Dutch and Low German 'wippen,' to swing or jump. The political sense borrows from fox-hunting: a 'whipper-in' was the rider who kept the hounds from straying, and by the 18th century the same word kept stray parliamentarians from wandering off before a vote. The kitchen sense—whipping cream—comes from that same brisk back-and-forth motion.