- noun a very stupid, lifeless or boring person. An obvious derivation of its component parts, this phrase is reinforced by its 19th-century American meaning of non-paying passengers or non-participants (from a ‘dead head’ of cattle).
- noun an idle person, a good-for-nothing
- noun a fan or devotee of the San Francisco rock group The Grateful Dead, who were popular in the late 1960s and early 1970s, and enjoyed a revival in the 1980s
- verb (of a vehicle) to run or drive empty or without passengers. This meaning, a relic of 19th-century cattle drives, is now rarely heard.