"It is in the New Testament where we find the words ghosts and spirits being used more often, interchangeably between translations. There are two Greek words that are used.
---The first is φάντασμα (phantasma), which literally means ‘apparition’ like the commonly understood word ‘ghost’.
---The word πνεῦμα (pneuma) means spirit, air, or breath. This can refer to what I described before as the essence of a being.
---It can also mean ‘demons’ when paired with the word ἀκάθαρτον (akatharton).
The most remembered New Testament passage regarding ghosts is Matthew 14:26. Whereas the KJV says: “And when the disciples saw him walking on the sea, they were troubled, saying, It is a 
spirit [phantasma]; and they cried out for fear,” the ESV says, “But when the disciples saw him walking on the sea, they were terrified, and said, ‘It is a ghost!’ and they cried out in fear.”
And Mark 6:49: “But when they saw him walking upon the sea, they supposed it had been a spirit [phantasma], and cried out” (KJV). “But when they saw him walking on the sea they thought it was a ghost, and cried out” (ESV).
On another occasion when Jesus suddenly appeared in the room with the disciples, they said: “But they were terrified and affrighted, and supposed that they had seen a spirit [Greek pneuma]” (Luke 24:37, KJV). The ESV says, “But they were startled and frightened and thought they saw a spirit.”
Notice in these examples how in its translations the ESV distinguishes between the two Greek words, whereas the KJV translates both the Greek pneuma and phantasma as “spirit”.
were seeing His spirit (a somewhat understandable reaction since He suddenly appeared in a locked room).
These first passages are referring to the occasion when Jesus was seen walking on the surface of the Sea of Galilee, and the Luke account is when the resurrected Jesus appeared to the disciples in the room.
Obviously, the disciples had never seen a man do anything like either of these events before, so their first thought was to invoke the supernatural, resorting to ideas from their culture to explain it. In the Luke account, they had seen Jesus die on the cross not too long before, so they thought they
And Jesus reinforces this in Luke 24:39 after his resurrection when He says:
“See my hands and my feet, that it is I myself. Touch me, and see. For a spirit does not have flesh and bones as you see that I have.” CMI