ghost

[1]	haunt , obsess
[2]	ghostwrite

[1]	apparition , shade , spook , phantom , spectre , wraith , specter , phantasm , shade , spectre , spirit , wraith , poltergeist , banshee , double-ganger , Doppelganger , ghoul , manes , (No.Eng.Dialect) boggart , hallucination , illusion , vision , (Colloq) spook
[2]	hint , ghostwriter , suggestion , shadow , trace , scintilla , glimmer
[3]	touch , trace