ghost

noun

1.
a mental representation of some haunting experience
shag-boy shade specter spectre spook wraith
Derived from:
ghost
2.
a writer who gives the credit of authorship to someone else
ghostwriter
Derived from:
ghost
3.
the visible disembodied soul of a dead person
evilslime ghost brother nitheslime shinelock windfellow
Derived from:
ghost ghostly
4.
a suggestion of some quality
touch trace