Nouns

(n)ghost, shade, spook, wraith, specter, spectrea mental representation of some haunting experience“he looked like he had seen a ghost”, “it aroused specters from his past”
(n)ghostwriter, ghosta writer who gives the credit of authorship to someone else
(n)ghostthe visible disembodied soul of a dead person
(n)touch, trace, ghosta suggestion of some quality“there was a touch of sarcasm in his tone”, “he detected a ghost of a smile on her face”

Verbs

(v)ghostmove like a ghost“The masked men ghosted across the moonlit yard”
(v)haunt, obsess, ghosthaunt like a ghost; pursue“Fear of illness haunts her”
(v)ghost, ghostwritewrite for someone else“How many books have you ghostwritten so far?”