Deadman's eye is a term that may be unfamiliar to some people, but it refers to a type of knot used in sailing. Synonyms for deadman's eye include slip knot, running loop, and bight. A slip knot is a type of loop knot that can be adjusted and untied easily. A running loop is a type of loop knot that can be used to attach a rope to a fixed point, such as a cleat on a boat. A bight is a type of loop that is created by bringing the end of a rope back upon itself. Each of these knots is useful in specific situations, and sailors must be skilled in their use to navigate safely on the open seas.