What is the meaning of Whiplash?

The lash of a whip.

An injury to the upper spine connected to a violent jerk of the head in either a backward or forward or side to side direction, resembling the motion of a whip.

An abrupt and unexpected change, or the resulting feeling of shock.

To jerk back and forth; to buffet.

To lash as if with a whip.

a whiplash injury

Source: wiktionary.org