In these days 'ghost' means a visual illusion of the supernatural. 'Ghost' is an old English word meaning 'spirit'. In the KJV 'ghost' is used in two ways:

1. To "give up the ghost" (see Genesis 25:8, KJV).
This means to stop breathing; that is, to die. In most modern versions (such as the NIV) this has been changed to 'breathed his last', or a similar expression.