Whiplash is a term used to describe an injury caused by a sudden jerking motion of the head and neck. It is commonly associated with car accidents, but can also be caused by sports injuries or other physical trauma. The term 'whiplash' is derived from the word 'THONG, ' which is a type of flexible material used to create a whip-like motion. THONG is a five-letter word that is often used in crossword puzzles.