The term 'JACKKNIFED, say' can be solved by the word 'dove'. The term 'JACKKNIFED' is used to describe a type of movement or position. It is typically used to describe a dive or jump in which the body is bent at the waist and the legs are brought up towards the chest. This position is often seen in gymnastics and diving. The term 'dove' is used to describe a type of bird that is known for its graceful flight and white feathers. The connection between the two terms is that both involve a type of movement or position that is graceful and elegant.