ghost
noun
a mental representation of some haunting experience
“he looked like he had seen a ghost”
“it aroused specters from his past”
a writer who gives the credit of authorship to someone else
Synonymsghostwriterthe visible disembodied soul of a dead person
a suggestion of some quality
“there was a touch of sarcasm in his tone”
“he detected a ghost of a smile on her face”
verb
move like a ghost
“The masked men ghosted across the moonlit yard”
haunt like a ghost; pursue
“Fear of illness haunts her”
write for someone else
“How many books have you ghostwritten so far?”
Synonymsghostwrite
Source: WordNet 3.1, Princeton University