whiplash
n.a neck injury caused by a sudden, sharp movement of the head. It often happens when a car is hit from behind.
n.an injury to the cervical spine caused by an abrupt jerking motion of the head, typically resulting from a rear-impact vehicle collision. Often used metaphorically to describe the shock of a sudden change in circumstances.
“He suffered from whiplash after the car accident.”
“The driver wore a neck brace for several weeks to help her recover from severe whiplash.”
“The sudden shift in government policy gave the markets a sense of whiplash, as investors struggled to adjust their portfolios to the new regulatory landscape.”
Often appears as the object of 'suffer from' or 'get'.
Univerbation of whip + lash.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.