A member of an intelligence agency whose identity or affiliation is kept confidential.
An undercover agent or spy.
A ghost or phantom.
A hobgoblin.
A scare or fright.
A psychiatrist.
A player who engages in hole carding by attempting to glimpse the dealer's hole card when the dealer checks under an ace or a 10 to see if a blackjack is present.
A metaphysical manifestation; an artificial distinction or construct.
To frighten or make nervous (especially by startling).
To become frightened (by something startling).
To haunt.