Ghost

1. (n) A disembodied soul; a soul or spirit of a deceased person; a spirit appearing after death. 2. (n) (by extension) Any faint shadowy semblance; an unsubstantial image. 3. (n) A false image formed in a telescope, camera, or other optical device by reflection from the surfaces of one or more lenses. 4. (n) An unwanted image similar to and overlapping or adjacent to the main one on a television screen, caused by the transmitted image being received both directly and via reflection. 5. (n) A nonexistent person invented to obtain some (typically fraudulent) benefit. 6. (n) A dead person whose identity is stolen by another (see ghosting). 7. (n) (Internet) An unresponsive user on IRC, resulting from the user's client disconnecting without notifying the server. 8. (n) (computing) A copy of a file or record. 9. (n) (theater) An understudy. 10. (n) (espionage) A covert (and deniable) agent. 11. (n) (cleaning) A faint image that remains after an attempt to remove graffiti. 12. (n) (video games) An opponent in a racing game that follows a previously recorded route, allowing players to compete against previous best times. 13. (n) Someone whose identity cannot be established because there are no records of such a person. 14. (n) (quantum mechanics) An unphysical state in a gauge theory. 15. (n) (computing, linguistics, attributive) A formerly nonexistent character that was at some point mistakenly encoded into a character set standard, which might have since become used opportunistically for some genuine purpose. 16. (n) (uncountable) A game in which players take turns to add a letter to a possible word, trying not to complete a word. 17. (n) (attributive, in names of species) White or pale. 18. (n) (attributive, in names of species) Transparent or translucent. 19. (n) (attributive) Abandoned. 20. (n) (attributive) Remnant; remains. 21. (n) (attributive) Perceived or listed but not real. 22. (n) (attributive) Of cryptid, supernatural or extraterrestrial nature. 23. (n) (attributive) Substitute. 24. (adj) (African-American Vernacular, slang) In the form be ghost: not present or involved; absent, gone. 25. (v) (transitive) (literary, poetic) Of a disembodied soul: to appear (somewhere or to someone) in the form of an apparition; to haunt. 26. (v) (transitive) (literary, poetic) To imbue (something) with a ghost-like effect or hue. 27. (v) (transitive) (by extension, figurative) To continuously cause (someone or something) trouble; specifically, to continuously be in the thoughts of (someone) in a disturbing manner; to perturb, to trouble. 28. (v) (transitive) (by extension, figurative) (slang) To kill (someone). 29. (v) (transitive) (by extension, figurative) (computing) (graphical user interface) To gray out (a visual element) to indicate that it is unavailable. 30. (v) (transitive) (by extension, figurative) (computing) (Internet) To forcibly disconnect (an IRC user) who is using one's reserved nickname. 31. (v) (transitive) (by extension, figurative) (chiefly social media, slang) To stop communicating with (someone) on social media, though text messages, etc., without explanation, especially as a way of ending a relationship; hence, to end a relationship with (someone) by stopping all communication without explanation. 32. (v) (transitive) (by extension, figurative) (chiefly UK, law enforcement) To transfer (a prisoner) to another prison, usually without first informing the prisoner. 33. (v) (transitive) Synonym of ghostwrite (“to write (a literary work or speech), or produce (an artistic work)), in the place of someone”); also, to carry out (an artistic performance) in the place of someone. 34. (v) (intransitive) To appear suddenly or move like a disembodied soul; specifically (often sports); also (transitive, dated) followed by the dummy subject it: to move easily and quietly without anyone noticing; to slip. 35. (v) (intransitive) Followed by for: synonym of ghostwrite (“to write a literary work or speech, or produce an artistic work, in the place of someone”); also, to carry out an artistic performance in the place of someone. 36. (v) (intransitive) (nautical) Of a sailing vessel: to sail seemingly with very little or no wind. 37. (n) (Christianity, literary, chiefly archaic) A spirit; a human soul. 38. (v) (intransitive) (obsolete) Apparently only in the writings of the Dutch-English physician Gideon Harvey (c. 1636–1640 – c. 1700–1702): to die, to expire. 39. (n) (writing) Ellipsis of ghostwriter. [A professional writer who is paid to write material that is officially credited to another person; one who writes on behalf of someone else, often for a celebrity.] 40. (n) (countable) Ellipsis of ghost pepper. [Synonym of bhut jolokia.]