Definitions
1.adjectiveWithout a head; decapitated."How did the headless horseman see to chase Ichabod?"
2.adjectiveWithout leadership."The headless army blundered along after the death of their general, accomplishing nothing."
3.adjective(of a phrase or compound) Not having a head morpheme or word.
4.adjectiveRunning without a graphical user interface; running without any attached output device (e.g., monitor) or input device (e.g., keyboard, mouse).
5.adjective(of beer) Without a head of foam.
6.adjectiveHeedless.