Zombie

Noun

1. A person, usually undead, animated by unnatural forces (such as magic), with no soul or will of his or her own.
2. An apathetic or slow-witted person. .mw-parser-output .defdate{font-size:smaller}
3. A human being in a state of extreme mental exhaustion.

   "After working for 18 hours on the computer, I was a zombie."

4. Someone or something that should be dead but is not.
5. An information worker who has signed a nondisclosure agreement.