What is the meaning of Ghost?

The spirit; the human soul.

The disembodied soul; the soul or spirit of a deceased person; a spirit appearing after death.

Any faint shadowy semblance; an unsubstantial image.

A false image formed in a telescope, camera, or other optical device by reflection from the surfaces of one or more lenses. (Can we verify this sense?)

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.

A ghostwriter.

A nonexistent person invented to obtain some (typically fraudulent) benefit.

A dead person whose identity is stolen by another. See ghosting. (Can we verify this sense?)

An unresponsive user on IRC, resulting from the user's client disconnecting without notifying the server.

An image of a file or hard disk.

An understudy. (Can we verify this sense?)

A covert (and deniable) agent.

The faint image that remains after an attempt to remove graffiti.

An opponent in a racing game that follows a previously recorded route, allowing players to compete against previous best times.

Someone whose identity cannot be established because there are no records of him/her. (Can we verify this sense?)

An unphysical state in a gauge theory.

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.

Clipping of ghost pepper.

A game in which players take turns to add a letter to a possible word, trying not to complete a word. (Can we verify this sense?)

White or pale.

Transparent or translucent.

Abandoned.

Remnant; the remains of a(n).

Perceived or listed but not real.

Of cryptid, supernatural or extraterrestrial nature.

Substitute.

To haunt; to appear to in the form of an apparition.

To die; to expire. (Can we verify this sense?)

To imbue with a ghost-like hue or effect.

To ghostwrite.

To sail seemingly without wind.

To copy a file or hard drive image. (Can we verify this sense?)

To gray out (a visual item) to indicate that it is unavailable.

To forcibly disconnect an IRC user who is using one's reserved nickname.

To appear or move without warning, quickly and quietly; to slip.

To transfer (a prisoner) to another prison without the prior knowledge of other inmates.

To kill.

To perform an act of ghosting: to break up with someone without warning or explanation; to ignore someone, especially on social media.

To provide the speaking or singing voice for another actor, who is lip-syncing.

Source: wiktionary.org