Definition of "headless" in English

adjective

1. Without a head (body part).

2. Without a head (hardware or device feature).

   • a headless nail;   a headless set screw

3. Without leadership.

   • The headless army blundered along after the death of their general, accomplishing nothing.

4. (linguistics, of a phrase or compound) Not having a head morpheme or word.

5. (computing) Running without a graphical user interface; running without any attached output device (e.g., monitor) or input device (e.g., keyboard, mouse).

6. (of beer) Without a head of foam.

7. (obsolete) Heedless.

   • 1579, E. K. (Edward Kirke?), Notes on Spenser’s The Shepheardes Calender If any one will rashly blame such his choice of old and unwonted words, him may I more justly blame and condemn, either of witless headiness in judging, or of headless hardiness in condemning.

8. (obsolete, firearms) Rimless, not having a cartridge case rim (flange).

   • A headless shell doesn't have a flange.