phantom
Definitions
A ghost or apparition of a dead person.
Something that is apparent to the senses but has no physical reality; an illusion.
A person or thing that is elusive or difficult to grasp.
Examples
The old mansion was rumored to be haunted by the phantom of a long-lost sea captain.
He felt a phantom pain in his leg, even though it had been amputated years ago.
The company was accused of creating phantom employees to inflate their payroll expenses.